35 Again, with what reverence for virginity has the holy Apostle spoken: “Concerning virgins I have no commandment of the Lord, but I give my counsel, as having obtained mercy of the Lord.” He has received no commandment, but a counsel, for that which beyond the law is not commanded, but is rather advised by way of counsel. Authority is not assumed but grace is shown, and this is not shown by anyone, but by him who obtained mercy from the Lord. Are then the counsels of these men better than those of the apostles? The Apostle says, “I give my counsel,” but they think it right to dissuade any from cultivating virginity.
Source: Letters (New Advent)