"The man who loves his life will lose it,
while the man who hates his life in this world
will keep it for eternal life." (John 12:25)
The 'paradox of happiness' says that those who seek it don't find it, whilst some who seek other things do find it. True! But here, Jesus speaks of the greatest paradox of them all: the paradox of life. Love your life, live for yourself, serve yourself, and you'll lose out on life. But hate your life, treat your own interests as nothing as you serve Jesus and others, and you find real, everlasting life.
We saw in John 12 on Sunday, that was Jesus' pattern. He gave up his life so that others might live. But the chapter is full of examples, positive and negative: people either living for themselves or living for Jesus. The best was Lazarus' sister Mary, who extravagantly poured perfume on Jesus as an expression of utter devotion to him.
If we know Jesus as the life-giver, the one who raises the dead to life (John 11), then our response is rightly to abandon ourselves to serving him. Kill ambitions for our own glory, or comfort, or ease - before they kill us! Live to serve Jesus, whatever the cost - because that's where true life is found.