How can I have confidence that I am a true Christian, and have passed from condemnation into eternal life?

Kevin DeYoung offers a threefold answer from 1 John.

I summarise:

1. Theological

I can have confidence that I am a true believer if I believe in Jesus Christ the Son of God (1 Jn 4:14-16; 5:1, 5; 5:11-13).  I believe that he is the Christ or the Messiah (1 Jn 2:22), that he is the Son of God (1 Jn 5:10), and that he has come in the flesh (1 Jn 4:2).

2. Moral

I can have confidence that I am a true believer if I live a righteoues life (1 Jn 3:6-9, 24).  This is not to claim to be sinless (1 Jn 1:9f).  But it is to acknowledge that those who habitually walk in wickedness cannot be confident of their salvation.  I am no longer a slave to sin (Rom 6).  Those who walk in the flesh will not inherit the kingdom of God (Gal 5).  A good tree cannot bear bad fruit and a bad tree cannot bear good fruit (Jn 15).

3. Social

I can have confidence that I am a true believer if love my fellow-Christians (1 Jn 4:7-12, 21).  If my heart and life, my money and possessions, are open to my brothers and sisters, then ternal life abides in me.

These, then, are the signs of our assurance:

‘We know we have eternal life if we love Jesus, we love his commands, and we love his people.’