I began to carefully scan the collection, and found that all my co-disciples were represented there, as well as hundreds whom I had never seen, and e… - William Quan Judge

It should be ever borne in mind that Patanjali had no need to assert or enforce the doctrine of reincarnation. That is assumed all through the Aphorisms. That it could be doubted, or need any restatement, never occurred to him, and by us it is alluded to, not because we have the smallest doubt of its truth, but only because we see about us those who never heard of such a doctrine, who, educated under the frightful dogmas of Christian priestcraft, imagine that upon quitting this life they will enjoy heaven or be damned eternally, and who not once pause to ask where was their soul before it came into the present body. Without Reincarnation Patanjali's Aphorisms are worthless. Take No. 18, Book III, which declares that the ascetic can know what were his previous incarnations with all their circumstances; or No. 13, Book II, that while there is a root of works there is fructification in rank and years and experience. Both of these infer reincarnation. In Aphorism 8, Book IV, reincarnation is a necessity. The manifestation, in any incarnation, of the effects of mental deposits made in previous lives, is declared to ensue upon the obtaining of just the kind of bodily and mental frame, constitution and environment as will bring them out. Where were these deposits received if not in preceding lives on earth — or even if on other planets, it is still reincarnation. And so on all through the Aphorisms this law is tacitly admitted. (Preface)

2. Concentration, or Yoga, is the hindering of the modifications of the thinking principle.
In other words, the want of concentration of thought is due to the fact that the mind — here called "the thinking principle" — is subject to constant modifications by reason of its being diffused over a multiplicity of subjects. So "concentration" is equivalent to the correction of a tendency to diffuseness, and to the obtaining of what the Hindus call "one-pointedness," or the power to apply the mind, at any moment, to the consideration of a single point of thought, to the exclusion of all else... Upon this Aphorism the method of the system hinges. The reason for the absence of concentration at any time is, that the mind is modified by every subject and object that comes before it; it is, as it were, transformed into that subject or object. The mind, therefore, is not the supreme or highest power; it is only a function, an instrument with which the soul works... (Book I, Concentration)

The fate of the suicide is horrible in general. He has cut himself off from his body by using mechanical means that affect the body, but cannot touch the real man. He then is projected into the astral world, for he has to live somewhere. There the remorseless law, which acts really for his good, compels him to wait until he can properly die. Naturally he must wait, half dead, the months or years which, in the order of nature, would have rolled over him before body and soul and spirit could rightly separate. He becomes a shade....