Mind precedes all mental states.
Mind is their chief; they are all mind-wrought. 
If with an impure mind a person speaks or acts, 
suffering follows him like the wheel that follows the foot of the ox.

Mind precedes all mental states. 
Mind is their chief; they are all mind-wrought. 
If with a pure mind a person speaks or acts, 
happiness follows him like his never-departing shadow. 
Dhammapada v. 1, 2

The mind is hard to check. It is swift and wanders at will.
To control it is good. A controlled mind is conducive to happiness.
The mind is very hard to perceive, extremely subtle and wanders at will.
Let the wise person guard it; a guarded mind is conducive to happiness.
Dhammapada v. 35, 36

A straightforward mind is the site of enlightenment.
Vimalakirti Sutra

It is a man's own mind, not his enemy or foe, that lures him to evil ways.

Consciousness will always be present, though a particular consciousness may cease. For example, the particular tactile
consciousness that is present within this human body will cease when the body comes to an end. Likewise, consciousnesses that are influenced by ignorance, by anger or by attachment, these too will cease. But the basic, ultimate, innermost subtle consciousness will always remain. It has no beginning, and it will have not end.
Answers: Discussions with Western Buddhists

Question: What is the nature of the mindstream that reincarnates from lifetime to lifetime?
Dalai Lama: ...If one understands the term "soul" as a continuum of individuality from moment to moment, from lifetime to lifetime, then one can say that Buddhism also accepts a concept of soul; there is a kind of continuum of consciousness. From that point of view, the debate on whether or not there is a soul becomes strictly semantic. However, in the Buddhist doctrine of selflessness, or "no soul" theory, the understanding is that there is no eternal, unchanging, abiding, permanent self called "soul." That is what is being denied in Buddhism.
Buddhism does not deny the continuum of consciousness. Because of this, we find some Tibetan scholars, such as the Sakya master Rendawa, who accept that there is such a thing as self or soul, the "kangsak ki dak" (Tib. gang zag gi bdag). However, the same word, the "kangsak ki dak," the self, or person, or personal self, or identity, is at the same time denied by many other scholars.
We find diverse opinions, even among Buddhist scholars, as to what exactly the nature of self is, what exactly that thing or entity is that continues from one moment to the next moment, from one lifetime to the next lifetime. Some try to locate it within the aggregates, the composite of body and mind. Some explain it in terms of a designation based on the body and mind composite, and so on.... One of the divisions of [the "Mind-Only"] school maintains there is a special continuum of consciousness called alayavijnana which is the fundamental consciousness.
Healing Anger: The Power of Patience from a Buddhist Perspective

Patricia Churchland: But do you think that there is something, I am not sure what to call it -- a kind of awareness that can exist independently of the brain? For example, something that survives death?
Dalai Lama: Generally speaking, awareness, in the sense of our familiar, day-to-day mental processes, does not exist apart from or independent of the brain, according to the Buddhist view. But Buddhism holds that the cause of this awareness is to be found in a preceding continuum of awareness, and that is why one speaks of a stream of awareness from one life to another. Whence does this awareness arise initially? It must arise fundamentally not from a physical base but from a preceding continuum of awareness.
The continuum of awareness that conjoins with the fetus does not depend upon the brain. There are some documented cases of advanced practitioners whose bodies, after death, escape what happens to everyone else and do not decompose for some time -- for two or three weeks or even longer. The awareness that finally leaves their body is a primordial awareness that is not dependent upon the body. There have been many accounts in the past of advanced practitioners remaining in meditation in this subtle state of consciousness when they died, and decomposition of their body was postponed although the body remained at room temperature.
Consciousness at the Crossroads: Conversations with the Dalai Lama on Brain Science and Buddhism

Question: What is the role that consciousness plays in the process of reincarnation?
Answer: In general, there are different levels of consciousness. The more rough, or gross, levels of consciousness are very heavily dependent upon the physical, or material, sphere. Since one's own physical aggregate (the body) changes from birth to birth, so too do these gross levels of consciousness. The more subtle the level of consciousness, however, the more independent of the physical sphere, and hence the more likely that it will remain from one life to the next. But in general, whether more subtle or more gross, all levels of consciousness are of the same nature.
Answers: Discussions with Western Buddhists

If the first true fact is that life in general is not easy, we should certainly not expect that seeing the nature of our mind will be simple. The actual nature of mind, on any level, is not very obvious. Even to identify and recognize correctly what is mind is extremely difficult. Just to start to try to see it, we need strong motivation. We need to be clear about why we would like to see the nature of our mind.
The Gelug/Kagyu tradition of Mahamudra

The basis on which Buddhist[s] accept the concept of rebirth is principally the continuity of consciousness . . . If you trace our present mind or consciousness back, then you will find that you are tracing the origin of the continuity of mind into an infinite dimension; it is, as you will see, beginningless.
Therefore there must be successive rebirths that allow that continuum of mind to be there.

The cells of our body are dying, the neurons in our brain are decaying, even the expressions on our face are always changing, depending on our mood. What we call our basic character is only a “mindstream,” nothing more. Today we feel good because things are going well; tomorrow we feel the opposite. Where did that good feeling go?
What could be more unpredictable than our thoughts and emotions: Do you have any idea what you are going to think or feel next? The mind, in fact, is as empty, as impermanent, and as transient as a dream. Look at a thought: It comes, it stays, and it goes. The past is past, the future not yet risen, and even the present thought, as we experience it, becomes the past.
The only thing we really have is nowness, is now.

The practice of mindfulness, of bringing the scattered mind home, and so of bringing the different aspects of our being into focus, is called Peacefully Remaining or Calm Abiding.
All the fragmented aspects of ourselves, which had been at war, settle and dissolve and become friends. In that settling we begin to understand ourselves more, and sometimes even have glimpses of the radiance of our fundamental nature.

We have been taught to spend our lives chasing our thoughts and projections. Even when the “mind” is talked about, it is only thoughts and emotions that are referred to; and when our researchers study what they imagine to be the mind, they look only at its projections. No one ever really looks into the mind itself, the ground from which all these expressions arise; and this has tragic consequences.

Confined in the dark, narrow cage of our own making that we take for the whole universe, very few of us can even begin to imagine another dimension of mind. Patrul Rinpoche tells the story of an old frog who had lived all his life in a dank well. One day a frog from the sea paid him a visit.
“Where do you come from?” asked the frog in the well.
“From the great ocean,” he replied.
“How big is your ocean?”
“It’s gigantic.”
“You mean about a quarter of the size of my well here?”
“Bigger.”
“Bigger? You mean half as big?”
“No, even bigger.”
“Is it . . . as big as this well?”
“There’s no comparison.”
“That’s impossible! I’ve got to see this for myself.”
They set off together. When the frog from the well saw the ocean, it was such a shock that his head just exploded into pieces.

Anyone looking honestly at life will see that we live in a constant state of suspense and ambiguity. Our minds are perpetually shifting in and out of confusion and clarity. If we could be confused all the time, that would at least make for some kind of clarity. What is really baffling about life is that sometimes, despite all our confusion, we can also be really wise!
This constant uncertainty may make everything seem bleak and almost hopeless; but if you look more deeply at it, you will see that its very nature creates “gaps,” spaces in which profound chances and opportunities for transformation are continuously flowering—if, that is, they can be seen and seized.

When we die we leave everything behind, especially this body we have cherished so much and relied upon so blindly and tried so hard to keep alive. But our minds are no more dependable than our bodies. Just look at your mind for a few minutes.
You will see that it is like a flea, constantly hopping to and fro. You will see that thoughts arise without any reason, without any connection. Swept along by the chaos of every moment, we are the victims of the fickleness of our minds. If this is the only state of consciousness we are familiar with, then to rely on our minds at the moment of death is an absurd gamble.

In the ordinary mind, we perceive the stream of thoughts as continuous, but in reality this is not the case. You will discover for yourself that there is a gap between each thought. When the past thought is past, and the future thought has not yet arisen, you will always find a gap in which the Rigpa, the nature of mind, is revealed. So the work of meditation is to allow thoughts to slow down, to make that gap become more and more apparent.

Because life is nothing but a perpetual fluctuation of birth, death, and transition, so bardo experiences are happening to us all the time, and are a basic part of our psychological makeup. Normally, however, we are oblivious to the bardos and their gaps, as our mind passes from one so-called solid situation to the next, habitually ignoring the transitions that are always occurring.
In fact, as the teachings can help us to understand, every moment of our experience is a bardo, as each thought and each emotion arises out of, and dies back into, the essence of mind. It is in moments of strong change and transition especially, the teachings make us aware, that the true skylike, primordial nature of mind will have a chance to manifest.

“Training” the mind does not in any way mean forcibly subjugating or brainwashing the mind. To train the mind is first to see directly and concretely how the mind functions, a knowledge that you derive from spiritual teachings and through personal experience in meditation practice. Then you use that understanding to tame the mind and work with it skillfully, to make it more and more pliable, so that you can become master of your mind and employ it to its fullest and most beneficial end.

The masters tell us that there is an aspect of our minds that is its fundamental basis, a state called “the ground of the ordinary mind.” It functions like a storehouse, in which the imprints of past actions caused by our negative emotions are all stored like seeds. When the right conditions arise, they germinate and manifest as circumstances and situations in our lives.

If we have a habit of thinking in a particular pattern, positive or negative, then these tendencies will be triggered and provoked very easily, and recur and go on recurring. With constant repetition our inclinations and habits become steadily more entrenched, and continue increasing and gathering power, even when we sleep. This is how they come to determine our life, our death, and our rebirth.