Glossa Ordinaria

The sun hath discolored me. It belongs to the sun to burn and to illuminate; so the true sun outwardly burns his own with persecutions, and by giving strength to resist he illuminates them. The sons of my mother. And as though she answers the objection of the weak who doubt: She shows from what quarter she bore the first fury of the persecutors, which appears the heavier from this, that it came from those of her own tribe. The sons, that is, the apostles destroyed our sect. Paul, the persecutor of the Church, was a son of her mother according to the flesh and to upbringing: and doing penance, converted to his sister's standards, he preached the faith which before he was destroying. They have set me. There was one vineyard of Christ in Jerusalem, namely the primitive Church, which was established on the day of Pentecost by the coming of the Holy Spirit, of which at that time the apostles were the keepers: but when persecution arose they were scattered into the regions of Judaea and Samaria, except the apostles, and so it came about that there were several vineyards, that is, in several places. And while the Jewish persecutors wished to trouble the Church, they were scattering the seed-plot of the word more widely, unwilling as they were, and by persecuting one they caused many to be established. When therefore she had said that she was afflicted by the parricidal hatred of the Synagogue, she at once subjoins how much she profited through this affliction, adding in the person of those to whom the care of preaching was committed: They have set me a keeper in the vineyards. Our vineyards are the actions which we cultivate by the practice of daily labor. But set as keepers in the vineyards, we do not keep our own vineyard: because while we are entangled in outside actions, we neglect the ministry of our own action. While I was keeping many vineyards, that I might gain others, in certain of them I sustained losses. The bitterness of the persecution of the sons of the Synagogue made me not keep my own vineyard, because, the evangelical doctrine being abandoned, they were compelling toward the distinctions of the legal observances.