Mark 3:13

(Vict. Ant. e Cat. in Marc.) He also instructs the Prelates of the Church to pass the night in prayer before they ordain, that their office be not impeded. When therefore, according to Luke, it was day, He called whom He would; for there were many who followed Him.

(in Marc. i. 16) After having forbidden the evil spirits to preach Him, He chose holy men, to cast out the unclean spirits, and to preach the Gospel; wherefore it is said, And he went up into a mountain, &c. (Luke 6) (ubi sup.) For it was not a matter of their choice and zeal, but of Divine condescension and grace, that they should be called to the Apostleship. The mount also in which the Lord chose His Apostles, shows the lofty righteousness in which they were to be instructed, and which they were about to preach to men.

Luke, however, says that He went up to pray, for after the showing forth of miracles He prays, teaching us that we should give thanks, when we obtain any thing good, and refer it to Divine grace.

Or spiritually, Christ is the mount, from which living waters flow, and milk is procured for the health of infants; whence the spiritual feast of fat things is made known, and whatsoever is believed to be most highly good is established by the grace of that Mountain. Those therefore who are highly exalted in merits and in words are called up into a mountain, that the place may correspond to the loftiness of their merits. It goes on: And they came unto him, &c. For the Lord loved the beauty of Jacob, (Ps. 46 Vulg.) that they might sit upon twelve thrones, judging the twelve tribes of Israel, (Matt. 19:28) who also in bands of threes and fours watch around the tabernacle of the Lord, and carry the holy words of the Lord, bearing them forward on their actions, as men do burdens on their shoulders.