Buddhist teachers have repeatedly pointed out the importance of being mentally strong. People who are mentally weak are more likely to suffer.

What is mental weakness? What kind of person is prone to mental weakness?

Strength and weakness may be hereditary to an extent; some people are naturally strong, others are naturally weak. But the more important factors are environment, educational background, and habitual dispositions. Relatively speaking, a person who is born into a wealthy family and educated in a prestigious institution is more likely to be mentally weak. As a result of this weakness, the person is fussy and difficult to work with. When this disposition develops into a habit, it becomes increasingly serious, to a point where all things are repulsive and unsatisfactory. In the end, such a person will find no meaning or happiness in life, and may even take drastic measures.

~Depicted from ARE YOU READY FOR HAPPINESS - How to Face Suffering and Happiness-How to Face Suffering

The first is that all sentient beings have been parents to one another since beginningless time. As such, the animals that we eat today surely have once been our parents too. Eating their meat will be like eating the flesh of our own parents or children. It is therefore a wrong thing to do even from the mundane perspective, let alone the supramundane point of view.

~Depicted from THE RIGHT VIEW - Why Vegetarian?

Since ancient times, the one thing human beings have always longed for is happiness. Yet, with all the progress in society, what we believe to be happiness has eluded us. The rapid decline in the index on global well-being has compelled all of us to rethink: What is happiness? How do we find it? In recent years, this topic has generated even greater interest.

~Depicted from ARE YOU READY FOR HAPPINESS - The Tibetan Buddhist View on Happiness

Feeling is a specific aspect of the mind. Objects like steel, cement, brick, glass, etc. do not have feeling – they do not feel either suffering or happiness. After we die, the body is just like a stone or brick. When it comes in contact with earth, water, fire, wind or anything on the outside, it does not react. It is no longer conscious and thus cannot feel suffering or happiness.

~Depicted from ARE YOU READY FOR HAPPINESS - How to Face Suffering and Happiness-How to Face Suffering

We should not think that anything that is not discovered by science or proven with logic does not exist, as not everything can be measured by hard data. Things like rebirth or soul cannot be checked by scientific instruments, at least not for the time being. However, as science continues to break new grounds, it is entirely possible that one day we might be able to do that. For now, logic, as we know it, is rendered helpless in the field of parapsychology because our sense organs are not equipped to provide us with useful data to do this kind of analysis.

~Depicted from THE HANDBOOKS' FOR LIFE JOURNEY - On Death And Rebirth-What Life Truly Is

There is an analogy for this. When ink is poured on the snow, the snow will be turned into ink color. After it melts, the color can still be seen on the ground. Similarly, if karma is born of defilements, the karmic mark will be left in the alaya consciousness after defilements are gone. Karma (or cause) is kind of a unique ability. Although our eyes cannot see how rice seeds germinate, they do have within themselves the capacity to do so. Likewise, when a karmic seed is planted in the alaya consciousness, it will yield fruit when all the right conditions come together. This fruit is also called karmic effect. And this particular capacity of the alaya consciousness to yield karmic fruit is the inherent nature of cause.

~Depicted from THE RIGHT VIEW - On Cause and Effect

There is suffering everywhere in the six realms of rebirth: if not suffering of suffering, it is suffering of change; if not suffering of change, it is all-pervasive suffering.  This is especially so in this degenerate time.  Even if we are unwilling to accept suffering, all of us have to confront it; we cannot ignore it. 

~Depicted from ARE YOU READY FOR HAPPINESS - How to Face Suffering and Happiness-How to Face Suffering

We neither came to nor will leave this world voluntarily. However unwilling, we all have to go when it is time, not by choice and certainly not on our terms. As well, we came in the same fashion. If there were free choices, no being would want to be born as an ox or a horse. But the reality is that we see these poor beings all the time. If free will were possible, all beings would naturally choose to be king in the human realm or someone like Indra, the King of the gods, instead of an ox or a horse. This clearly shows that beings cannot choose the timing or the form of birth. One just has to come when it is time. Why?

~Depicted from THE RIGHT VIEW - The Twelve Nidanas¹—the sequence of cyclic existence

What does oneness refer to? Normally, the sutric system maintains that sentient beings are not buddhas but ordinary beings encumbered with defilement, who can transform their minds into the wisdom of the buddha only through Dharma practice over numerous lives. But the view set forth in the third turning of the wheel of Dharma, in particular that of tantra, is that ground and fruition are in fact one, that ground is fruition and fruition is ground. In other words, sentient beings are buddhas and buddhas are sentient beings; the two are one and the same.

~Depicted from GATEWAY TO VAJRAYANA PATH - The Completion Stage —the skillful means to realize emptiness