Sheep

Boyd’s Bible Dictionary:

An important animal among Hebrews, and a main source of wealth
Shepherd’s occupation highly respectable (Gen. 4:22And she again bare his brother Abel. And Abel was a keeper of sheep, but Cain was a tiller of the ground. (Genesis 4:2); Ex. 3:11Now Moses kept the flock of Jethro his father in law, the priest of Midian: and he led the flock to the backside of the desert, and came to the mountain of God, even to Horeb. (Exodus 3:1); 1 Sam. 16:1111And Samuel said unto Jesse, Are here all thy children? And he said, There remaineth yet the youngest, and, behold, he keepeth the sheep. And Samuel said unto Jesse, Send and fetch him: for we will not sit down till he come hither. (1 Samuel 16:11); Job 42:1212So the Lord blessed the latter end of Job more than his beginning: for he had fourteen thousand sheep, and six thousand camels, and a thousand yoke of oxen, and a thousand she asses. (Job 42:12)), though odious to Egyptians. Used for sacrifices (Ex. 20:24; 29:3824An altar of earth thou shalt make unto me, and shalt sacrifice thereon thy burnt offerings, and thy peace offerings, thy sheep, and thine oxen: in all places where I record my name I will come unto thee, and I will bless thee. (Exodus 20:24)
38Now this is that which thou shalt offer upon the altar; two lambs of the first year day by day continually. (Exodus 29:38)
; Lev. 9:33And unto the children of Israel thou shalt speak, saying, Take ye a kid of the goats for a sin offering; and a calf and a lamb, both of the first year, without blemish, for a burnt offering; (Leviticus 9:3)); for food (1 Sam. 25:1818Then Abigail made haste, and took two hundred loaves, and two bottles of wine, and five sheep ready dressed, and five measures of parched corn, and an hundred clusters of raisins, and two hundred cakes of figs, and laid them on asses. (1 Samuel 25:18)). Wool used for clothing (Lev. 13:4747The garment also that the plague of leprosy is in, whether it be a woollen garment, or a linen garment; (Leviticus 13:47)). Skins used for tabernacle coverings (Ex. 25:55And rams' skins dyed red, and badgers' skins, and shittim wood, (Exodus 25:5)). Paid as tribute (2 Kings 3:44And Mesha king of Moab was a sheepmaster, and rendered unto the king of Israel an hundred thousand lambs, and an hundred thousand rams, with the wool. (2 Kings 3:4)). Sheep and shepherd employed much figuratively (2 Chron. 18:1616Then he said, I did see all Israel scattered upon the mountains, as sheep that have no shepherd: and the Lord said, These have no master; let them return therefore every man to his house in peace. (2 Chronicles 18:16); Psa. 119:176176I have gone astray like a lost sheep; seek thy servant; for I do not forget thy commandments. (Psalm 119:176); Matt. 9:3636But when he saw the multitudes, he was moved with compassion on them, because they fainted, and were scattered abroad, as sheep having no shepherd. (Matthew 9:36); John 10:1111I am the good shepherd: the good shepherd giveth his life for the sheep. (John 10:11); Heb. 13:2020Now the God of peace, that brought again from the dead our Lord Jesus, that great shepherd of the sheep, through the blood of the everlasting covenant, (Hebrews 13:20)). The common sheep of Syria and Palestine was the broad-tailed variety.

Concise Bible Dictionary:

Sheep were bred in great numbers in Palestine, and formed a large part of the property of the Israelites. The species common there was the broad tailed sheep with horns (Ovis laticaudatus and Ovis aries). In Palestine they follow the shepherd and know his voice, and will not follow a stranger. Sheep and lambs were constantly offered in sacrifice. The morning and evening lamb and the passover lambs were all types of the sacred One who was called “the Lamb of God which taketh away the sin of the world.”
Symbolically sheep are figurative of mankind, as being prone to wander: “All we like sheep have gone astray; we have turned every one to his own way” (Isa. 53:66All we like sheep have gone astray; we have turned every one to his own way; and the Lord hath laid on him the iniquity of us all. (Isaiah 53:6); Luke 15:4-74What man of you, having an hundred sheep, if he lose one of them, doth not leave the ninety and nine in the wilderness, and go after that which is lost, until he find it? 5And when he hath found it, he layeth it on his shoulders, rejoicing. 6And when he cometh home, he calleth together his friends and neighbors, saying unto them, Rejoice with me; for I have found my sheep which was lost. 7I say unto you, that likewise joy shall be in heaven over one sinner that repenteth, more than over ninety and nine just persons, which need no repentance. (Luke 15:4‑7)). The Lord said, “My sheep shall never perish.” The Good Shepherd calls His own sheep by name, and when brought into His own company they have perfect security, liberty, and sustenance (John 10:99I am the door: by me if any man enter in, he shall be saved, and shall go in and out, and find pasture. (John 10:9)). The Lord led His sheep out of the Jewish fold: these were united with His “other sheep” (Gentile believers), that they all should become “one flock” with one Shepherd (John 10:3, 163To him the porter openeth; and the sheep hear his voice: and he calleth his own sheep by name, and leadeth them out. (John 10:3)
16And other sheep I have, which are not of this fold: them also I must bring, and they shall hear my voice; and there shall be one fold, and one shepherd. (John 10:16)
). In the future judgment of the nations, those saved are called “sheep,” in distinction from the lost, who are called “goats” (Matt. 25:31-4631When the Son of man shall come in his glory, and all the holy angels with him, then shall he sit upon the throne of his glory: 32And before him shall be gathered all nations: and he shall separate them one from another, as a shepherd divideth his sheep from the goats: 33And he shall set the sheep on his right hand, but the goats on the left. 34Then shall the King say unto them on his right hand, Come, ye blessed of my Father, inherit the kingdom prepared for you from the foundation of the world: 35For I was an hungred, and ye gave me meat: I was thirsty, and ye gave me drink: I was a stranger, and ye took me in: 36Naked, and ye clothed me: I was sick, and ye visited me: I was in prison, and ye came unto me. 37Then shall the righteous answer him, saying, Lord, when saw we thee an hungred, and fed thee? or thirsty, and gave thee drink? 38When saw we thee a stranger, and took thee in? or naked, and clothed thee? 39Or when saw we thee sick, or in prison, and came unto thee? 40And the King shall answer and say unto them, Verily I say unto you, Inasmuch as ye have done it unto one of the least of these my brethren, ye have done it unto me. 41Then shall he say also unto them on the left hand, Depart from me, ye cursed, into everlasting fire, prepared for the devil and his angels: 42For I was an hungred, and ye gave me no meat: I was thirsty, and ye gave me no drink: 43I was a stranger, and ye took me not in: naked, and ye clothed me not: sick, and in prison, and ye visited me not. 44Then shall they also answer him, saying, Lord, when saw we thee an hungred, or athirst, or a stranger, or naked, or sick, or in prison, and did not minister unto thee? 45Then shall he answer them, saying, Verily I say unto you, Inasmuch as ye did it not to one of the least of these, ye did it not to me. 46And these shall go away into everlasting punishment: but the righteous into life eternal. (Matthew 25:31‑46)).

From Manners and Customs of the Bible:

Sheep and goats are allowed to mingle during the day while at pasturage, but at night are separated. Thus the Saviour seeks to illustrate the truth that though righteous and wicked are now together, there will come a time of separation.