Schism (σχίσμα)

Concise Bible Dictionary:

The word is rendered “divisions” in 1 Corinthians 1:1010Now I beseech you, brethren, by the name of our Lord Jesus Christ, that ye all speak the same thing, and that there be no divisions among you; but that ye be perfectly joined together in the same mind and in the same judgment. (1 Corinthians 1:10), etc., and refers to divisions caused by parties in the church. In view of the unity of the Spirit, schism cannot be regarded in any other light than as sin. The unity contemplated in the church was not merely that of being gathered together in assembly. The Corinthians were exhorted: “That ye all speak the same thing, and that there be no divisions [schisms] among you; but that ye be perfectly joined together in the same mind and in the same judgment” (1 Cor. 1:1010Now I beseech you, brethren, by the name of our Lord Jesus Christ, that ye all speak the same thing, and that there be no divisions among you; but that ye be perfectly joined together in the same mind and in the same judgment. (1 Corinthians 1:10); 1 Cor. 11:1818For first of all, when ye come together in the church, I hear that there be divisions among you; and I partly believe it. (1 Corinthians 11:18); 1 Cor. 12:2525That there should be no schism in the body; but that the members should have the same care one for another. (1 Corinthians 12:25)). The modern ideas of agreeing “to differ,” or of “unity only in essentials,” are not found in scripture, but the contrary. At Philippi the saints were exhorted to walk by the same rule, to mind the same thing; and then is added “If in anything ye be otherwise minded, God shall reveal even this unto you” (Phil. 3:1515Let us therefore, as many as be perfect, be thus minded: and if in any thing ye be otherwise minded, God shall reveal even this unto you. (Philippians 3:15)). The “unity of the Spirit” cannot be lightly disregarded. Christians are exhorted to use diligence to keep it in the uniting bond of peace (Eph. 4:33Endeavoring to keep the unity of the Spirit in the bond of peace. (Ephesians 4:3)). There are different lines of ministry, as is manifest in the apostles Paul and John, but all true ministry tends to one end—Christ; and hence such differences in no way clash with the unity of the Spirit. See HERESY.

From Anstey’s Doctrinal Definitions:

A schism is an inward split or rift among Christians (1 Cor. 11:1818For first of all, when ye come together in the church, I hear that there be divisions among you; and I partly believe it. (1 Corinthians 11:18) – marginal reading in the KJV). Those involved in a schism will still meet outwardly with those with whom they differ, but probably unhappily (Rom. 16:1717Now I beseech you, brethren, mark them which cause divisions and offences contrary to the doctrine which ye have learned; and avoid them. (Romans 16:17); 1 Cor. 1:10; 3:3; 11:1810Now I beseech you, brethren, by the name of our Lord Jesus Christ, that ye all speak the same thing, and that there be no divisions among you; but that ye be perfectly joined together in the same mind and in the same judgment. (1 Corinthians 1:10)
3For ye are yet carnal: for whereas there is among you envying, and strife, and divisions, are ye not carnal, and walk as men? (1 Corinthians 3:3)
18For first of all, when ye come together in the church, I hear that there be divisions among you; and I partly believe it. (1 Corinthians 11:18)
). This was the case with the Corinthians. The Apostle Paul warned them that if schisms existed, and were not dealt with and judged as evil, “there must also be heresies” that would grow out of those schisms (1 Cor. 11:18-1918For first of all, when ye come together in the church, I hear that there be divisions among you; and I partly believe it. 19For there must be also heresies among you, that they which are approved may be made manifest among you. (1 Corinthians 11:18‑19)). Hence, an inward split left unjudged will develop into an outward split. (See Heresy.)
In Romans 16:1717Now I beseech you, brethren, mark them which cause divisions and offences contrary to the doctrine which ye have learned; and avoid them. (Romans 16:17), Paul says, Mark them which cause divisions and offences [occasions of stumbling]” contrary to the doctrine which ye have learned; and avoid them.” This refers to those who cause these inward rifts among the saints. Those who “cause” divisions are the leaders or instigators, not those who simply follow in a movement. Thus, we are to distinguish the leaders from those led astray in these issues. We are to “avoid” the leaders, but reach out and try to help those who are being drawn away in a divisive movement.
Paul says that the means by which these divisive workers get a following is through “good words and fair speeches,” and the kind of people who are deceived by them are those who are “simple” and “unsuspecting” (Rom. 16:1818For they that are such serve not our Lord Jesus Christ, but their own belly; and by good words and fair speeches deceive the hearts of the simple. (Romans 16:18)). Absalom is a type of a divisive man in the assembly (2 Sam. 15-18). He drew ones after himself, who “in their simplicity,” “knew not anything” (2 Sam. 15:1111And with Absalom went two hundred men out of Jerusalem, that were called; and they went in their simplicity, and they knew not any thing. (2 Samuel 15:11)). His method was to agree with those who had a complaint, and to kiss them. The result was that he “stole the hearts of the men of Israel (2 Sam. 15:1-61And it came to pass after this, that Absalom prepared him chariots and horses, and fifty men to run before him. 2And Absalom rose up early, and stood beside the way of the gate: and it was so, that when any man that had a controversy came to the king for judgment, then Absalom called unto him, and said, Of what city art thou? And he said, Thy servant is of one of the tribes of Israel. 3And Absalom said unto him, See, thy matters are good and right; but there is no man deputed of the king to hear thee. 4Absalom said moreover, Oh that I were made judge in the land, that every man which hath any suit or cause might come unto me, and I would do him justice! 5And it was so, that when any man came nigh to him to do him obeisance, he put forth his hand, and took him, and kissed him. 6And on this manner did Absalom to all Israel that came to the king for judgment: so Absalom stole the hearts of the men of Israel. (2 Samuel 15:1‑6)). The forming of his party didn’t happen overnight; it took “four years” (2 Sam. 15:77And it came to pass after forty years, that Absalom said unto the king, I pray thee, let me go and pay my vow, which I have vowed unto the Lord, in Hebron. (2 Samuel 15:7)). (The KJV says “forty,” but it is apparently a Hebrew copyist’s mistake.) Slowly but surely, Absalom swung many in Israel after himself and the result was division in Israel.