Boyd’s Bible Dictionary:
(Isa. 40:11; Zech. 11:4; Matt. 26:31; Luke 12:32; 1 Pet. 5:2-3)[SHEEP.]
Concise Bible Dictionary:
A term used in the O. T. for Israel as sheep gathered by God as their Shepherd, and called Jehovah's flock (Psa. 77:20; Psa. 107:41; Jer. 13:17). It is also applied to those of Israel that were gathered to Christ when on earth. To these He added the Gentile believers; and all were united into one flock (not “one fold”), with Christ as the one Shepherd (John 10:16). When the leaders of Israel were to be judged as not caring for the Lord's flock, the prophet speaks of the remnant as the poor of the flock (Zech. 11:7, 11: Compare Luke 6:20).
The Lord also spoke to His disciples as a little flock, bidding them not to fear: it was their Father's good pleasure to give them the kingdom (Luke 12:32). In Paul's address to the elders of Ephesus he exhorts them to take heed unto all the flock: the wolves would not spare them. Paul commended the shepherds to God and to the word of His grace (Acts 20:28-29: Compare 1 Pet. 5:2-3).