John Chrysostom
Having put them to shame by what happens among outsiders, the Apostle then points to himself. This is the best manner of teaching, and therefore he constantly acts in this way. What then does "not as uncertainly" mean? I have in view, he says, a definite goal. I do not struggle vainly and to no purpose, as you do. Indeed, what benefit is there for you in entering idol temples and, as it were, displaying your perfection? None. I am not so. Everything I do, I do for the salvation of my neighbors. If I display perfection, it is for them. If condescension, it is for them. If superiority over Peter by taking nothing, it is so that they may not be scandalized. If humiliation beyond all, by being circumcised and cutting my hair, it is so that they may not stumble.
Read more (169 words)
This is what "not as uncertainly" means. But tell me, why do you eat in the temples? You cannot present any sound reason. Food does not bring you nearer to God. If you eat, you gain nothing. If you do not eat, you lose nothing. Therefore you go in vain and without purpose. This is what "uncertainly" means. "I fight not as one who merely beats the air." By these words he also expresses that he does not act vainly and without purpose. I have an enemy, he says, whom I strike, namely the devil. But you do not strike him. You simply exhaust your strength. He speaks thus because he spares them. Having earlier given them a severe rebuke, here he softens the reproach, postponing the stronger blow to the end of the discourse. Now he says that they do this vainly and to no purpose. Later he proves that by such conduct they bring destruction upon their own heads and, besides harming the brethren, themselves become guilty.