Separation

From Anstey’s Doctrinal Definitions:

This refers to the Christian’s conviction to keep himself clear of the world—both in a religious and a secular sense. The following things are some reasons why God insists on separation in a Christian’s life:
Firstly, separation is necessary because association with the world will result in the restricting of the believer’s affection for Christ and His people. Simply put, it brings coldness into the soul. In 2 Corinthians 6:12-18,12Ye are not straitened in us, but ye are straitened in your own bowels. 13Now for a recompence in the same, (I speak as unto my children,) be ye also enlarged. 14Be ye not unequally yoked together with unbelievers: for what fellowship hath righteousness with unrighteousness? and what communion hath light with darkness? 15And what concord hath Christ with Belial? or what part hath he that believeth with an infidel? 16And what agreement hath the temple of God with idols? for ye are the temple of the living God; as God hath said, I will dwell in them, and walk in them; and I will be their God, and they shall be my people. 17Wherefore come out from among them, and be ye separate, saith the Lord, and touch not the unclean thing; and I will receive you, 18And will be a Father unto you, and ye shall be my sons and daughters, saith the Lord Almighty. (2 Corinthians 6:12‑18) the Apostle Paul explains that our “bowels” (affections) will become “straitened” (restricted) if we neglect to walk in separation from the world. This sad effect is seen in the case of Ephraim who “mixeth himself with the peoples” of the nations (Hosea 7:88Ephraim, he hath mixed himself among the people; Ephraim is a cake not turned. (Hosea 7:8)). The result was that he became “like a silly dove without heart” (Hos. 7:1111Ephraim also is like a silly dove without heart: they call to Egypt, they go to Assyria. (Hosea 7:11)). His association with the world took his heart away from the Lord.
Secondly, association with the world spoils the believer’s appetite for the Word of God. We see this illustrated in the history of Israel in the wilderness. God gave them “manna” for their food (Ex. 16). The New Testament tells us that this is a type of Christ who is the spiritual food for the believer (John 6:31-5831Our fathers did eat manna in the desert; as it is written, He gave them bread from heaven to eat. 32Then Jesus said unto them, Verily, verily, I say unto you, Moses gave you not that bread from heaven; but my Father giveth you the true bread from heaven. 33For the bread of God is he which cometh down from heaven, and giveth life unto the world. 34Then said they unto him, Lord, evermore give us this bread. 35And Jesus said unto them, I am the bread of life: he that cometh to me shall never hunger; and he that believeth on me shall never thirst. 36But I said unto you, That ye also have seen me, and believe not. 37All that the Father giveth me shall come to me; and him that cometh to me I will in no wise cast out. 38For I came down from heaven, not to do mine own will, but the will of him that sent me. 39And this is the Father's will which hath sent me, that of all which he hath given me I should lose nothing, but should raise it up again at the last day. 40And this is the will of him that sent me, that every one which seeth the Son, and believeth on him, may have everlasting life: and I will raise him up at the last day. 41The Jews then murmured at him, because he said, I am the bread which came down from heaven. 42And they said, Is not this Jesus, the son of Joseph, whose father and mother we know? how is it then that he saith, I came down from heaven? 43Jesus therefore answered and said unto them, Murmur not among yourselves. 44No man can come to me, except the Father which hath sent me draw him: and I will raise him up at the last day. 45It is written in the prophets, And they shall be all taught of God. Every man therefore that hath heard, and hath learned of the Father, cometh unto me. 46Not that any man hath seen the Father, save he which is of God, he hath seen the Father. 47Verily, verily, I say unto you, He that believeth on me hath everlasting life. 48I am that bread of life. 49Your fathers did eat manna in the wilderness, and are dead. 50This is the bread which cometh down from heaven, that a man may eat thereof, and not die. 51I am the living bread which came down from heaven: if any man eat of this bread, he shall live for ever: and the bread that I will give is my flesh, which I will give for the life of the world. 52The Jews therefore strove among themselves, saying, How can this man give us his flesh to eat? 53Then Jesus said unto them, Verily, verily, I say unto you, Except ye eat the flesh of the Son of man, and drink his blood, ye have no life in you. 54Whoso eateth my flesh, and drinketh my blood, hath eternal life; and I will raise him up at the last day. 55For my flesh is meat indeed, and my blood is drink indeed. 56He that eateth my flesh, and drinketh my blood, dwelleth in me, and I in him. 57As the living Father hath sent me, and I live by the Father: so he that eateth me, even he shall live by me. 58This is that bread which came down from heaven: not as your fathers did eat manna, and are dead: he that eateth of this bread shall live for ever. (John 6:31‑58)). However, there came a time in their journey through the wilderness when they became tired of the manna, and this was because they were lusting after the foods of Egypt—a type of the world (Num. 11:4-64And the mixt multitude that was among them fell a lusting: and the children of Israel also wept again, and said, Who shall give us flesh to eat? 5We remember the fish, which we did eat in Egypt freely; the cucumbers, and the melons, and the leeks, and the onions, and the garlick: 6But now our soul is dried away: there is nothing at all, beside this manna, before our eyes. (Numbers 11:4‑6)). Thus, believers who hanker after worldly pleasures and entertainments will have their appetite for the Word of God spoiled.
Thirdly, association with the world desensitizes the believer’s moral standards. The Christian who associates with worldly people will be influenced by them. He will begin to think and act like them, and their worldly values and moral standards will become his. The Word of God says, “Be not deceived: evil communications corrupt good manners” (1 Cor. 15:3333Be not deceived: evil communications corrupt good manners. (1 Corinthians 15:33)). Lot’s moral standards dropped down to the level of the men of Sodom (Gen. 19). This is seen in the alarming fact that he offered his daughters to the men of the city.
Fourthly, association with the world hinders the believer’s spiritual growth. Again, this is seen in the case of Ephraim who mixed himself among the Gentiles. The result was that he was like a “cake not turned ” (Hos. 7:88Ephraim, he hath mixed himself among the people; Ephraim is a cake not turned. (Hosea 7:8)). That is, he was like a half-cooked pancake—being only half developed.
Fifthly, association with the world causes the Christian to lose his spiritual energy in his personal life. Joshua warned the people in his day that if they settled down among the godless Canaanites, they would lose their power to resist them (Josh. 23:12-1312Else if ye do in any wise go back, and cleave unto the remnant of these nations, even these that remain among you, and shall make marriages with them, and go in unto them, and they to you: 13Know for a certainty that the Lord your God will no more drive out any of these nations from before you; but they shall be snares and traps unto you, and scourges in your sides, and thorns in your eyes, until ye perish from off this good land which the Lord your God hath given you. (Joshua 23:12‑13)). They would no longer be able to stand before their enemies. Again, with Ephraim it says, “Strangers have devoured his strength” (Hos. 7:99Strangers have devoured his strength, and he knoweth it not: yea, gray hairs are here and there upon him, yet he knoweth not. (Hosea 7:9)). Samson is another illustration of this. By his association with the worldly Philistine girl (Delilah), “His strength went from him” (Jud. 16:19).
Sixthly, association with the world will cause the believer to lose his spiritual discernment. Again, the example of Ephraim illustrates this. It says, “Strangers have devoured his strength, and he knoweth it not: yea, gray hairs are here and there upon him, yet he knoweth not” (Hos. 7:99Strangers have devoured his strength, and he knoweth it not: yea, gray hairs are here and there upon him, yet he knoweth not. (Hosea 7:9)). Having associated with the world, he became insensible to his personal state. There was spiritual decay, and he didn’t know it! It was the same with Samson. He didn’t seem to know that he had lost it either. It says, “And he wist not that the LORD was departed from him” (Jud. 16:20). The Laodiceans were also devoid of their true state and imagined that they were right and good, but their state was actually obnoxious to the Lord (Rev. 3:14-2214And unto the angel of the church of the Laodiceans write; These things saith the Amen, the faithful and true witness, the beginning of the creation of God; 15I know thy works, that thou art neither cold nor hot: I would thou wert cold or hot. 16So then because thou art lukewarm, and neither cold nor hot, I will spue thee out of my mouth. 17Because thou sayest, I am rich, and increased with goods, and have need of nothing; and knowest not that thou art wretched, and miserable, and poor, and blind, and naked: 18I counsel thee to buy of me gold tried in the fire, that thou mayest be rich; and white raiment, that thou mayest be clothed, and that the shame of thy nakedness do not appear; and anoint thine eyes with eyesalve, that thou mayest see. 19As many as I love, I rebuke and chasten: be zealous therefore, and repent. 20Behold, I stand at the door, and knock: if any man hear my voice, and open the door, I will come in to him, and will sup with him, and he with me. 21To him that overcometh will I grant to sit with me in my throne, even as I also overcame, and am set down with my Father in his throne. 22He that hath an ear, let him hear what the Spirit saith unto the churches. (Revelation 3:14‑22)).
Lastly, association with the world destroys the believer’s personal testimony. Lot is an example. By living in Sodom (a type of this world in its moral corruption) he lost his power in testimony. When he went to call his sons-in-law out of that city which was under judgment, his words to them seemed “as one that mocked” (Gen. 19:1414And Lot went out, and spake unto his sons in law, which married his daughters, and said, Up, get you out of this place; for the Lord will destroy this city. But he seemed as one that mocked unto his sons in law. (Genesis 19:14)). They didn’t take him seriously because his life told another story. Christians generally have not kept separate from the world, and as a result a poor testimony has been rendered before the world. It’s a wonder that anyone turns to the Lord and gets saved. Gandhi, of India, said that if it weren’t for Christians he would have become one!