13 Thinking therefore of these things, let us arouse ourselves; for if you bring not your own endeavours to the task, every thing on our part is to no purpose. And why so? Because it is not with the office of teaching, as it is with other arts. For the silversmith, when he has fabricated a vessel of any kind, and laid it aside, will find it on the morrow just as he left it. And the worker in brass, and the stone-cutter, and every other artificer, will each again take his own work in hand, whatever it is, just in the state he quitted it. But it is not so with us, but altogether the reverse; for we have not lifeless vessels to forge, but reasonable souls. Therefore we do not find you such as we leave you, but when we have taken you, and with manifold labour moulded, reformed you and increased your ardour on your departing from this place, the urgency of business, besetting you on every side, again perverts you, and causes us increased difficulty. Therefore, I supplicate and beseech you to put your own hand to the work; and when you depart hence, to show the same earnest regard for your own safety, that I have here shown for your amendment.
Source: Homilies on the Statues (New Advent)