The subjects of sacrifice and self-sacrifice are raised in many religions. The meaning of sacrifice is rather trivial: a person of faith must give away part of his assets to get the desired blessing or the favor of God. This is, so to speak, the exact meaning. The symbolic meaning of sacrifice for the seeker states that you can’t get anything for free on the Path of Truth. For instance, in order to find bliss, you have to give away your sufferings, some of which are very dear to you.
Some mystics make a deliberate sacrifice at the price known to them only, in order to gain new opportunities in their Work. There are also mystics who sacrifice themselves to God in their entirety. This sacrifice gives them something that can neither be explained nor understood by those who have never done the same.