This teaching by Khenchen Thrangu Rinpoche might also be helpful:
28. On Vajra Commitments (Samaya)
There is another issue connected with empowerments that is of great concern to many people, which is samaya. Many people wonder whether it is good to receive empowerments at all, because each empowerment seems to come with commitments (Tib. samaya); and are these not a source of great danger to those who are unable to keep them? The presentation of the commitments connected with empowerments as very, very strict and presented as very dangerous for a reason. It is presented that way in order to encourage practitioners to engage in virtue. To understand why this is done, you must remember, the primary responsibility of a guru is to, one way or another, get you to do the right thing. In order to do that, they will sometimes say, “Having received this empowerment you are bound by such and such samaya, and should you transgress it you will be in great peril.” Presenting it this way is done in order to get you to do the right thing. But you should not think that having received empowerments places you in peril. Rather receiving empowerments is always a source of benefit.
Now, if someone receiving an empowerment were to utterly repudiate the entire thing and generate intense antipathy for the whole process and tradition, that is to consciously engage in a complete reversal of virtue and wrong-doing and do everything they could wrong, well obviously, under those circumstances, that person might fall to a lower rebirth. But you are not going to fall to a lower rebirth simply because you receive an empowerment and thereafter can’t fulfill all your commitments.
To understand this, it may help to consider the word for “commitment” which in Sanskrit was translated as “samaya” and was translated into Tibetan as dam tshig, which means, “words of promise” or “words of bond.” Now, the idea of “words of promise” is not that if you transgress against these rules or regulations, you will fall fast into vajra hell after your death. Rather the point is that having received empowerment and instruction, you should practice it. If you don’t actually practice, simply receiving empowerment is insufficient. As we have seen, one of the things that keeps practice going is the momentum of commitment. So, if you make a commitment when you receive empowerment to practice, the momentum of that commitment will enable you to carry it through. In other words, the commitment or promise that you make during the empowerment is actually a source of great help or assistance to you. Having received the empowerment and then not doing the practice is not going to cause you to fall to lower states; it’s simply that the promise didn’t really fulfill its function, because it didn’t produce the momentum of commitment and, therefore, practice.
So samaya should be regarded more as a useful tool than a threat. The purpose of it is to give you the means to establish a momentum of diligent practice, and this is established because you approach the empowerment with that attitude of enthusiastic commitment. If you ask, “Well do I need to keep samaya?” You do need to keep samaya, because you need to keep your promises. But you should not keep them out of fear.
--- Thrangu Rinpoche The Interval between Life and Death