On life

...In the smallest particle of matter there is a world of creatures, living beings, animals, entelechies, souls. Each portion of matter may be conceived as like a garden full of plants and like a pond full of fishes. But each branch of every plant, each member of every animal, each drop of its liquid parts is also some such garden or pond. And though the earth and the air which are between the plants of the garden, or the water which is between the fish of the pond, be neither plant nor fish; yet they also contain plants and fishes, but mostly so minute as to be imperceptible to us. Thus there is nothing fallow, nothing sterile, nothing dead in the universe, no chaos, no confusion save in appearance, somewhat as it might appear to be in a pond at a distance, in which one would see a confused movement and, as it were, a swarming of fish in the pond, without separately distinguishing the fish themselves. (Monadology, §66-69)

On death

Thus the soul changes its body only by degrees, little by little, so that it is never all at once deprived of all its organs; and there is often metamorphosis in animals, but never metempsychosis or transmigration of souls; nor are there souls entirely separate nor unembodied spirits . God alone is completely without body. It also follows from this that there never is absolute birth nor complete death, in the strict sense, consisting in the separation of the soul from the body. What we call births are developments and growths, while what we call deaths are envelopments and diminutions. (Monadology, §72-73)

On monads

The Monad, of which we shall here speak, is nothing but a simple substance, which enters into compounds. By 'simple' is meant 'without parts.' And there must be simple substances, since there are compounds; for a compound is nothing but a collection or aggregatum of simple things. Now where there are no parts, there can be neither extension nor form nor divisibility. These Monads are the real atoms of
nature and, in a word, the elements of things. No dissolution of these elements need be feared, and there is no conceivable way in which a simple substance can be destroyed by natural means. For the same reason there is no conceivable way in which a simple
substance can come into being by natural means, since it cannot be formed by the combination of parts. Thus it may be said that a Monad can only come into being or come to an end all at once; that is to say, it can come into being only by creation and come to an end only by annihilation, while that which is compound comes into being or comes to an end by parts. Further, there is no way of explaining how a Monad can be altered in quality or internally changed by any other created thing; since it is impossible to change the place of anything in it or to conceive in it any internal motion which could be produced, directed, increased or diminished therein, although all this is possible in the case of compounds, in which there are changes among the parts. The Monads have no windows, through which anything could come in or go out. Accidents cannot separate themselves from substances nor go about outside of them, as the 'sensible species' of the Scholastics used to do. Thus neither substance nor accident can come into a Monad from outside. (Monadology, §1-7)

Quotations
A few selections from the Theodicy
Leibniz on himself and other philosophers - By D. Rutherford
Quotations - from Truth & Reality
Quotations - from Wikiquote