In vol. 1 of his immensely helpful series Classical Pastoral Care, Thomas Oden quotes John Wyclif on the three duties of a pastor:
“Therefore, the first condition of the pastor is to cleanse his own spring, that it may not infect the word of God … The pastor has a threefold office: first, to feed his sheep spiritually on the Word of God, that through pastures ever green they may be initiated into the blessedness of heaven. The second pastoral office is to purge wisely the sheep of disease, that they may not infect themselves and others as well. And the third is for the pastor to defend his sheep from ravening wolves, both sensible and insensible” (Wyclif, The Pastoral Office, Part 2, sec. 1, LCC XIV, p. 48).