The circumlocution before us, which runs, And He opened His mouth, perhaps gracefully intimates by the mere pause that the sermon will be somewhat longer than usual, unless, perchance, it should not be without meaning, that now He is said to have opened His own mouth, whereas under the old law He was accustomed to open the mouths of the prophets.
Opening his mouth. It is a Hebraism, to signify he began to speak. (Witham)
This is a common expression in Scripture, to signify something important is about to be spoken. Thus it is used in various other places, as "Job opening his mouth cursed his day, and said "Daniel, chap. x. et alibi. (Jansenius)
And why is it added, says St. Chrysostom "and opening his mouth "without doubt that we might know, that not only when he spoke, but even when silent, he gave instruction: sometimes, therefore, he opened his mouth; at other times he spoke by his very actions. (Hom. xv.)
And in this way He was then employed. For it is said, that He opened His mouth, and taught them. And wherefore is the clause added, He opened His mouth? To inform you that in His very silence He gave instruction, and not when He spoke only: but at one time by opening His mouth, at another uttering His voice by the works which He did.
But when you hear that He taught them, do not think of Him as discoursing with His disciples only, but rather with all through them.
For since the multitude was such as a multitude ever is, and consisted moreover of such as creep on the ground, He withdraws the choir of His disciples, and makes His discourse unto them: in His conversation with them providing that the rest also, who were yet very far from the level of His sayings, might find His lesson of self-denial no longer grievous unto them. Of which indeed both Luke gave intimation, when he said, that He directed His words unto them: and Matthew too, clearly declaring the same, wrote, His discip...
Why does the evangelist say, "He opened His mouth"? It would appear that this is superfluous; but it is not. For He also taught without opening His mouth. How did He do this? By His life and His miracles. But now He opens His mouth and teaches.
He taught not only His disciples, but the multitude as well. He begins with the beatitudes, "Blessed are they," just as David began the Psalms with the beatitude, "Blessed is the man" (Ps. 1:1).
