Psalms 131:2

Then he goes on: Like a weaned child upon his mother's breast, so will you reward my soul. We are told that when Isaac was weaned Abraham made a feast because now that he was weaned he was on the verge of boyhood and was passing beyond milk food. The Apostle feeds all that are imperfect in the faith and still babes in the things of God with the milk of knowledge. Thus to cease to need milk marks the greatest possible advance. Abraham proclaimed by a joyful feast that his son had come to stronger meat, and the Apostle refuses bread to the carnal-minded and those that are babes in Christ. And so the Prophet prays that God, because he has not lifted up his heart, nor walked amid things great and wonderful that are above him, because he has not been humble-minded but did lift up his soul, may reward his soul, lying like a weaned child upon his mother: that is to say that he may be deemed worthy of the reward of the perfect, heavenly and living bread, on the ground that by reason of his works already recorded he has now passed beyond the stage of milk.

"If I had not lowly thoughts, but have lifted up my soul, as one taken from his mother's breast, such the reward for my soul" [Psalm 131:2]. He seemeth as it were to have bound himself by a curse: ...as though he had been going to say, Let it so happen to me. "As one taken away from his mother's breast, may be my soul's reward." Ye know that the Apostle saith to some weak brethren, "I have fed you with milk, and not with meat; for hitherto ye were not able to bear it, neither yet now are ye able." [1 Corinthians 3:2] There are weak persons who are not fit for strong meat; they wish to grasp at that which they cannot receive: and if they ever do receive, or seem to themselves to receive what they have not received, they are puffed up thereby, and become proud thereupon; they seem to themselves wise men. Now this happeneth to all heretics; who since they were animal and carnal, by defending their depraved opinions, which they could not see to be false, were shut out of the Catholic Church. ... ...It has been evidently explained, my brethren, where God would have us to be humble, where lofty. Humble, in order to provide against pride; lofty, to take in wisdom. Feed upon milk, that thou mayest be nourished; be nourished, so that thou mayest grow; grow, so that thou mayest eat bread. But when thou hast begun to eat bread, thou wilt be weaned, that is, thou wilt no longer have need of milk, but of solid food. This he seemeth to have meant: "If I had not lowly thoughts, but have lifted up my soul:" that is, if I was not an infant in mind, I was in wickedness. In this sense, he said before, "Lord, my heart was not lifted up, nor mine eyes raised on high: I do not exercise myself in great matters, nor in wonderful things above me." Behold, in wickedness I am an infant. But since I am not an infant in understanding, "If I had not lowly thoughts, but have lifted up my soul," may that reward be mine which is given unto the infant that is weaned from his mother, that I may at length be able to eat bread. ...For it is not an infant, but a grown child that is taken away from milk; he who is weak in his earliest infancy, which is his true infancy, is upon his mother's breast: if perchance he hath been taken away from the milk, he perisheth. It is not without a reason then that it is added, "Upon his mother's breast." For all may be weaned by growing. He who groweth, and is…