A word naturally of frequent occurence in Scripture. Sometimes the word "pastor" is used instead (Jer. 2:8; 3:15; 10:21; 12:10; 17:16). This word is used figuratively to represent the relation of rulers to their subjects and of God to his people (Ps. 23:1; 80:1; Isa. 40:11; 44:28; Jer. 25:34, 35; Nahum 3:18; John 10:11, 14; Heb. 13:20; 1 Pet. 2:25; 5:4).
The duties of a shepherd in an unenclosed country like Palestine were very onerous. "In early morning he led forth the flock from the fold, marching at its head to the spot where they were to be pastured. Here he watched them all day, taking care that none of the sheep strayed, and if any for a time eluded his watch and wandered away from the rest, seeking diligently till he found and brought it back. In those lands sheep require to be supplied regularly with water, and the shepherd for this purpose has to guide them either to some running stream or to wells dug in the wilderness and furnished with troughs. At night he brought the flock home to the fold, counting them as they passed under the rod at the door to assure himself that none were missing. Nor did his labours always end with sunset. Often he had to guard the fold through the dark hours from the attack of wild beasts, or the wily attempts of the prowling thief (see 1 Sam. 17:34).", Deane's David.
Easton's Bible Dictionary. M.G. Easton. 1897.