Theophylact of Ohrid

Or this is addressed to the Pharisees; as if He said, O Pharisees, what you have spoken in darkness, that is, all your endeavours to tempt me in the secrets of your hearts, shall be heard in the light, for I am the light, and in My light shall be known whatsoever your darkness devises. And what you have spoken in the ear and in closets, that is, whatsoever in whispers you have poured into one another's ears, shall be proclaimed on the housetops, that is, was as audible to me as if it had been cried aloud on the housetops. …

Catena Aurea by Aquinas ↗

Bede

Nothing, however, is covered that will not be revealed, nor hidden that will not be known. And how in the present age does the hypocrisy of many long remain hidden? Therefore, it must be understood about the future time, when God will judge the hidden things of men. For just as one of the friends of blessed Job very truly said: The praise of the wicked is brief, and the joy of the hypocrite is but for a moment. If his arrogance rises to the heavens, and his head touches the clouds, he will be lost in the end like dung (Job. XX). …

On the Gospel of Luke ↗

Bonaventure

Second, with regard to the certitude of the cause rendering credible information, he adds: Nothing however is covered that shall not be revealed, nor hidden that shall not be known: so that by covered is understood knowledge lying hidden in the intellect, and by hidden, delight lurking in the affections: both of which are manifest to God, according to that passage of Jeremiah 17: "I the Lord, searching hearts and reins, who give to each one" etc.; in the Psalm: "God, who searches hearts and reins." And therefore, because it will be …

Commentary on Luke, Chapter 12 ↗