Gregory the Dialogist

For from my infancy compassion grew up with me, and from my mother's womb it came forth with me. For though commiseration was a thing at his own command, that it should gain growth with himself, yet it is plain that it was not a thing at his own command that it should 'come forth from the womb along with himself.' Therefore it is plain that he attributes nothing to his own goodness, in that surely he bears witness that he received this same by the gift of his creation. …

Morals on the Book of Job, Book XXI ↗

Thomas Aquinas

He shows why he was merciful in this way in two ways: first, from long-studied habit he began in childhood, and so he says, "Since mercy has increased in me from my infancy." As he grew in years, so he practiced the works of mercy more. Second, because he had a natural inclination to mercy, like other men commonly have certain inclinations to different virtues, and so he says, "it came forth with me from the womb of my mother," because from the first days of my birth I was disposed to give mercy promptly.

Commentary on Job ↗