Galatians 6:4

A hermit said to a brother, 'Do not measure yourself against your brother, saying that you are more serious or more chaste or more understanding than he is. But be obedient to the grace of God, in the spirit of poverty, and in love unfeigned. The efforts of a man swollen with vanity are futile. It is written, "Let him that thinks he stands take heed lest he fall" (1 Cor. 10:12); "let your speech be seasoned with salt" (Col. 4:6) and so you will be dependent upon Christ.'

"But let each person prove." Let each person examine his own deeds which he himself performed in life. For by doing this he will prepare himself for better things. Yet this is not the act of one who judges, but of one who humbles himself. For it is not fitting, he says, to boast; if anything, at least do not, he says, boast as the Pharisee did against your neighbor, but against yourself. (see Luke 18:9-14) — [THEODORET] In another way. But if you wish to make a display of your dignity, he says, inspect your own life; and even if you find it blameless, boast of yourself according to your own standard, provided indeed that this is what you ought to do. [end of the excerpt by Theodoret] —

(Verse 4) But let each one test his own work, and then his reason to boast will be in himself alone and not in his neighbor. The meaning is this: You, who consider yourself spiritual and stronger in the weakness of others, should not focus on the weakness of the one who is falling but on your own strength. For it is not because someone else cannot perfectly transition from Judaism to Christianity that you are a perfect Christian; rather, if your own conscience does not bother you, you have reason to boast in yourself and not in someone else. An athlete is not strong because they have defeated the weak and overpowered the feeble limbs of their opponent, but if they are strong in their own strength, not in the weakness of others. It can be understood another way: one who has a conscience of good work and considers themselves should not boast about it to others, pour out their own praise to the world, share it with everyone, and seek glory from the favor of others. Rather, they should have glory within themselves and say: But far be it from me to boast except in the cross of our Lord Jesus Christ, through whom the world has been crucified to me, and I to the world. He who seeks glory from another, is neither crucified with the world, nor is he himself crucified with Christ. He has indeed received his reward, that which he sought from men.