Gregory of Nyssa

God commands us by His prophet not to esteem any new God to be God, and not to worship any strange God. Now it is clear that that is called new which is not from everlasting, and on the contrary, that is called everlasting which is not new. He, then, who does not believe that the Only-begotten God is from everlasting of the Father does not deny that He is new, for that which is not everlasting is confessedly new; and that which is new is not God, according to the saying of Scripture, "there shall not be in thee any new God." …

On The Faith ↗

Thomas Aquinas

The entire law of Christ depends upon charity. And charity depends on two precepts, one of which concerns loving God and the other concerns loving our neighbor. Now God, in delivering the law to Moses, gave him Ten Commandments written upon two tablets of stone. Three of these Commandments that were written on the first tablet referred to the love of God; and the seven Commandments written on the other tablet related to the love of our neighbor. The whole law, therefore, is founded on these two precepts. …

Explanation of the Ten Commandments ↗

Bonaventure

And from this fact, that He is the pious worshiper of Himself, the true witness to Himself, and the holy lover of Himself, there comes down from heaven a threefold radiation in the mind, according to the three commandments of the first tablet. For the creature must behave in relation to God in a manner that is pious, true, and holy. …

Collations on the Hexaemeron, Collation 21 ↗