““Therefore bear fruit in keeping with repentance; and do not suppose that you can say to yourselves, ‘We have Abraham for our father’; for I say to you that from these stones God is able to raise up children to Abraham. “And the axe is already laid at the root of the trees; therefore every tree that does not bear good fruit is cut down and thrown into the fire.” (Matthew 3:8–10 LSB)  https://accordance.bible/link/read/LSB#Matt._3:8

Can you prove you are a christian? What evidence before God is there that we are indeed loving Him most and first with our lives? God will not be deceived by our words, that we loved Him or that we were christians, He will look into the depths of our hearts and He will bring forth our true deeds to either reward us or condemn us. John warned his followers to do deeds in keeping with repentance. The sinners deeds are obvious; drunkenness, sexual immorality, cursing, hating, selfishness, and the like. So too the Christian’s deeds are obvious; loving kindness, generosity, serving, sacrificing, forgiving, encouraging, blessing and the like. Talk is cheap, saying we are christians and that we go to church doesn’t make us Christian. Living like Jesus makes us christian. Certainly there are words we confess, Jesus is Lord, and things we believe, He died for our sins and rose from the dead as evidence that His payment was sufficient, but it is our deeds that give credence to our words and our beliefs. It is what we do that reveals what we truly believe. If God is our first love and greatest treasure then we will work hard and give generously of time and treasure to seeing His kingdom come and His will being done on earth as it is in heaven. If something else is truly our first love then our deeds, our giving of our time and treasure, will reflect that. What do your deeds reveal as your first love? Is it really God or something else?