poimaino (4165), "to act as a shepherd" (from poimen, "a shepherd"), is used (a) literally, <Luke 17:7>, RV, "keeping sheep," for KJV, "feeding cattle"; <1 Cor. 9:7>, (b) metaphorically, "to tend, to shepherd"; said of Christ <Matt. 2:6>, RV, "shall be Shepherd of" (for KJV, "shall rule"); of those who act as spiritual shepherds under Him, <John 21:16>, RV, "tend" (for KJV "feed"), so <1 Pet. 5:2; Acts 20:28>, "to feed" ("to tend" would have been a consistent rendering; a shepherd does not only "feed" his flock); of base shepherds, <Jude 12>. See RULE.
Note: In <John 21:15,16,17>, the Lord, addressing Peter, first uses No. 1, bosko <v. 15> then No. 2, poimaino <v. 16>, and then returns to bosko <v. 17>. These are not simply interchangeable (nor are other variations in His remarks); a study of the above notes will show this. Nor, again, is there a progression of ideas. The lesson to be learnt, as Trench points out (Syn. Sec. xxv), is that, in the spiritual care of God's children, the "feeding" of the flock from the Word of God is the constant and regular necessity; it is to have the foremost place. The tending (which includes this) consists of other acts, of discipline, authority, restoration, material assistance of individuals, but they are incidental in comparison with the "feeding."
(from Vine's Expository Dictionary of Biblical Words)
(Copyright (C) 1985, Thomas Nelson Publishers)