Assuredly, I say to you, there are some standing here who shall not taste death till they see the Son of Man coming in His kingdom. Whoever loses his psyche for Christ's sake will find it. It is total abandonment of self-will. . . Others, however, understand this expression quite differently here and in the parallel texts. Eternal salvation is not something which we buy.
Eternal salvation is unmerited.
Nowhere in this passage is belief in Christ even mentioned. Second, those being addressed here are believers, not unbelievers. Believers already have eternal salvation. Rather, it is a rewards concept. There, nearly identical language is used and it clearly deals with possible rewards for people who are already eternally secure.