John Chrysostom

Next, pursuing his contrast, he states the cause of this, saying, "he knoweth not because they are spiritually discerned:" i.e. the things asserted require faith, and to apprehend them by reasonings is not possible, for their magnitude exceeds by a great deal the meanness of our understanding. …

Homily on 1 Corinthians 7 ↗

Theophylact of Ohrid

The spiritual man, he says, knows all things; he knows that everything here is temporary, while the future is permanent; he knows that he will receive salvation, and that the unfaithful will be punished. Therefore he also exposes them, "yet he himself is judged by no one," that is, they cannot expose him, for the one who sees perceives both his own things and those belonging to the unseeing; on the contrary, they, like blind men, see neither their own things nor those that belong to him.

Commentary on 1 Corinthians ↗

Irenaeus

...he who is truly spiritual will interpret by pointing out, in regard to every one of the things which have been spoken, to what special point in the dispensation of the Lord is referred, and [by thus exhibiting] the entire system of the work of the Son of God, knowing always the same God, and always acknowledging the same Word of God, although He has [but] now been manifested to us; acknowledging also at all times the same Spirit of God, although He has been poured out upon us after a new fashion in these last times, [knowing that …

Against Heresies (Book IV, Chapter 33) ↗

Thomas Aquinas

Then when he says, But the spiritual man, he gives the reason why spiritual things are imparted to spiritual men. First, he gives the reason; secondly, he clarifies it (v. 16). The reason given is this: Spiritual things should be entrusted to one who can discern: "The ear discerns with words" (Jb 12:11); but the spiritual man is such. Therefore, spiritual things should be entrusted to him. And this is what he says: The spiritual man judges all things, and he himself is judged of no man. …

Commentary on 1 Corinthians ↗