Augustine of Hippo

But what He says may cause perplexity: For with what judgment ye judge, ye shall be judged; and with what measure ye mete, it shall be measured to you again. Is it the case, then, that if we shall judge any thing with a rash judgment, God will also judge rashly with respect to us? Or if we shall measure any thing with an unjust measure, is there with God also an unjust measure, according to which it shall be measured to us again? …

Sermon On The Mount 2.18.62 ↗

Thomas Aquinas

The reason follows: For with the judgment you pronounce, you will be judged, i.e., according the judgment with which you have judged you will be judged: "The wicked are ensnared in the work of their own hands" (Ps 9:16); and below (26:52): "He that strikes with the sword shall die by the sword." Or, in this way: Those who judge should fear that the Lord might allow them to be punished with this judgment: "Woe to you, destroyer, who yourself have not been destroyed" (Is 33:1). The measure you give will be the measure you get... …

Commentary on Matthew ↗

Bernard of Clairvaux

It is not, I think, that such a soul should any longer be afraid to say: "My beloved to me"; for from the fact that it feels itself loving, and loving vehemently, it does not doubt that it is loved no less vehemently in return; and from its own singular intention, solicitude, care, effort, diligence, and zeal, with which it incessantly and ardently watches over how to please God, it recognizes without doubt all these same things equally in him, remembering his promise: "In what measure you shall have measured, it shall be measured to …

Sermons on the Song of Songs, Sermon 69 ↗