Through his death and resurrection, Jesus opened the way to God and paid the penalty for our sins. As a result, he can promise us that if we have faith in him, our sins are forgiven and salvation is guaranteed. The promise that Jesus makes in Mark 8:35, that those who lose their life for the sake of the gospel will save it, is a promise we can trust. Whoever comes to true faith in Jesus Christ, whoever denies himself and takes up his cross, such a person will save his life.
In calling his disciples and the crowd to a life of self-denial and cross bearing, Jesus is not asking them (and us) to do anything that he has not done himself. He’s not sitting in heaven bossing us around from a distance. He is our Shepherd, leading us from the front (Psalm 23:1–6, Mark 6:34). He is our Shepherd who has given himself to save his sheep (Mark 10:45, John 10:1–30), who knows about our suffering and temptations (Hebrews 4:15), and who calls us to follow him with the assurance that he has provided salvation for us, and he will continue to care for us.
31 Alors il commença à leur apprendre qu'il fallait que le Fils de l'homme souffre beaucoup, qu'il soit rejeté par les anciens, par les principaux sacrificateurs et par les scribes, qu'il soit mis à mort, et qu'il ressuscite trois jours après.