John 12:24-25
24 Verily, verily, I say unto you, Except a corn of wheat fall into the ground and die, it abideth alone: but if it die, it bringeth forth much fruit.
25 He that loveth his life shall lose it; and he that hateth his life in this world shall keep it unto life eternal.
The Grace New Testament Commentary - John 12:25-26
12:25-26 Jesus then spoke of the symbolic death of His disciples. Eternal rewards are in view as in the parallel passages in the Synoptics (Matt 10:38-39; 16:24-27; Mark 8:34-38; Luke 9:23-27; 12:16-34; 14:26-35).
The believer "who loves his life will lose it." That is, he will forfeit fullness of life in the life to come, and now as well. "He who hates his life in this world will keep it for eternal life." This is a rare reference by Jesus in John's Gospel not to the present possession of eternal life (e.g., John 3:16; 5:24; 6:35, 47), but to a possible future abundant experience of that life. The same idea is in Matt 19:29; Gal 6:7-9; and 1 Tim 6:12, 19.
The issue is serving and following Jesus - discipleship, not eternal salvation. Just as Jesus gave up His life, so should His followers (cf. 1 John 3:16-18). The Christian who squanders his life on worldly pursuits will forfeit an abundant eternal experience. As in many passages on rewards (e.g., 1 Thess 5:10, 23; Rev 21:6-7; 22:12-17), the Lord gives believers both the possibility of fullness of life forever and the promise of being forever "where I am" (see esp. 1 Thess 5:10). "God the Father will honor" those who serve His Son. The honors will be announced at the believer's judgment day, the Judgment Seat of Christ (cf. 1 Cor 9:24-27: 2 Cor 5:10: 1 John 2:28; 4:17).
Charles Bing - Grace, Salvation, and Discipleship - Finding Your Life, Matthew 10:39; 16:25-26 (cf. Mark 8:35-38; Luke 9:24-26; John 12:25)
(Salvation) Interpretation: If a person lives for himself, he will not gain salvation or he will lose salvation. But if a person forsakes his selfish desires, he will gain eternal life.
(Discipleship) Interpretation: If a believer lives for himself, he will miss the abundant life that God has for him. But if he forsakes his selfish desires, he will find the abundant life.
These statements explain why the invitation to discipleship that we discussed above should be accepted. Whoever does so saves his life, or his soul. Immediately, when some hear the language about saving (or losing) one's soul, they assume a (Salvation) interpretation, taking it as a reference to salvation of one's spirit from hell. This is a problem created by the English translations of the Bible.
The word soul (psychē) is the same word translated life in these passages (which is how some Bible versions translate it). It refers to life in its essence, the immaterial part of a person comprised of mind, will, and emotions that forms one's identity. Your life is who you really are. This statement is helpful because it uses the word "himself" for "life:" "For what profit is it to a man if he gains the whole world, and is himself destroyed or lost?" (Luke 9:25).
It is also important to understand how the word save (sōzō) is used. As discussed earlier, it does not always refer to eternal salvation. It simply means to deliver, to preserve from some danger or loss. Usually, we determine its meaning from the context. Here, Jesus has just talked about losing our own desires and subsuming them to His desires for us. If someone wants to hang on to his own desires and agenda in this world ("save his life") he will lose what life is really all about - experiencing the will of God and the fullness of God's life. He may gain everything this world has to offer, but miss the greater experience of God's life now and as a reward in the future (v. 27).
Taken in this way, we see that the word lose (apollumi) is the opposite of save. It does not mean to be eternally lost in hell but has the idea of ruin or forfeit. To lose your life is to ruin it or forfeit what God would have it be. Someone can have eternal life yet waste the opportunity to enjoy life's fullness by living for God now.
If we interpret this statement by Jesus (Salvifically), we miss a profound principle for the Christian life. If we seek the things this world has to offer while avoiding the hardships that can be involved with knowing Jesus Christ, we lose the very quality of life we really desire. It is only by losing our life to God that we get it back fuller and richer than ever. When life ceases to be the issue, life becomes the reality.
We may think it is too painful to give up a consuming habit, a toxic relationship, or our own ambitions and plans. What we will discover is that in losing our life, we find true life - the fullness of God's abundant life now and forever.