This point is also stressed by the Gdan-bzhi and the G'a-sbyor-if the yogi uses this teaching at the wrong time, he has thus murdered the Buddha-like self body. If he has taken the precepts of Tantra, he is then violating the eighth rule of the basic precepts of Tantra, and he is exposed to the danger of falling into hell. Therefore, he should clearly understand the time factor, and industriously study the signs of death to the coming of death. When the signs appear, he should try to prevent it by all possible means. If everything is done but to no avail, he should know that it is the right time to apply this teaching. According to the commentary on Gdan-bzhi, Bhaba Bhadras, he should practise this teaching, or make his preparations six months before the time of death. For this reason one

should carefully study the lines in the books concerning the signs of death.

Furthermore the Tantra of Gdan-bzhi says:

"The best condition under which one transforms (his soul)
Is without disease or other illness."

The Transformation Yoga is applied under condition that one has not caught any disease. If the practitioner is caught by disease, he cannot perform the transformation in a perfect way, though he may have tried his utmost.

In the case of an old, miserable man with great sufferings who foresees the coming of his death and intends to leave this world by means of the Transformation Yoga before the time of death comes, it is still forbidden. It is also forbidden in the case of one who suffers from an unbearable sickness. Some ignorant people say that in the former case, the old man is allowed to use the Transformation Yoga (before his time comes). [**]

The main instruction on the Transformation Yoga consists of two practices. The Tantra of Vajra says:

"The foundation of all (feelings) should be purified.
After the purification the transformation from existence is applied;
Otherwise it will be futile."

"The foundation of all (feelings)" implies that the human body is the foundation or base of all agreeable or disagreeable feelings. (Purification means that through the practice of Heat Yoga the body and mind are purified.) Without purifying the body through practicing the Heat

[paragraph continues] Yoga it will be useless and futile to perform the Transformation Yoga. This is said in Bhaba Bhadras, because the Tumo practice is the very foundation of Transformation Yoga. The Tantra of Vajra Dakini also says:

"By means of the Vase Breathing the door is bound (opened).
Thus, the hole of the door is purified."