John Chrysostom

Then, as he is ever wont to do, unto the former subject whence he digressed to say these things, he brings back his discourse as follows: "Wherefore, brethren, desire earnestly to prophesy, and forbid not to speak with tongues." For this too is his wont, not only to work out what is before him, but also starting from that to set right whatever seems to him in any way akin to it, and again to return to the former, so as not to appear to wander from the subject. …

Homily on 1 Corinthians 37 ↗

Theophylact of Ohrid

Having spoken about the gifts, he inserted a word about women: now he speaks again about the gifts, and gives first place to the gift of prophecy, saying: "desire earnestly," and second place to the gift of tongues. He did not say: permit, but: "do not forbid." This is how we usually speak about matters that are not necessary, neither permitting nor forbidding.

Commentary on 1 Corinthians ↗

Thomas Aquinas

Here the Apostle concludes the general admonition. In regard to this he does three things: first, he admonishes them to desire all the gifts, saying: therefore, to speak in tongues is good. But earnestly desire to prophesy. The reason for this, as it says in Pr (29:18): "Where there is no prophecy, the people cast off restraint." And "prophecy" is taken here as explained in this entire chapter. And yet, although you may desire to prophesy, do not forbid speaking in tongues, lest dissension arise.

Commentary on 1 Corinthians ↗