1 Corinthians 11:19

“For there must be also heresies among you etc.] This is a reason why he was ready to believe there might be something of truth in the report he had received of the divisions among them; for if there were heresies, false doctrines, and bad principles, among them, such as were subversive of the fundamentals of Christianity, as the denial of the resurrection of the dead, etc. it was no wonder that there were schisms and factions among them, since heresies generally issue in them. These, the apostle says, “must be”; because God has decreed they shall, whose counsel is immutable, and his purpose unalterable; and since this always was the case, that there were false prophets under the former…”

“heresies--Not merely "schisms" or "divisions" (Co1 11:18), which are "recent dissensions of the congregation through differences of opinion" [AUGUSTINE, Con. Crescon. Don. 2.7, quoted by TRENCH, Greek Synonyms of the New Testament], but also "heresies," that is, "schisms which have now become inveterate"; "Sects" [CAMPBELL, vol. 2, pp. 126, 127]: so Act 5:17; Act 15:5 translate the same Greek. At present there were dissensions at the love-feasts; but Paul, remembering Jesus' words (Mat 18:7; Mat 24:10, Mat 24:12; Luk 17:1) foresees "there must be (come) also" matured separations, and established parties in secession, as separatists. The "must be" arises from sin in professors necessarily…”

“For there must be - It is necessary (δεῖ dei); it is to he expected; there are reasons why there should be. What these reasons are he states in the close of the verse; compare Matthew 18:7; 2 Peter 2:1; 2 Peter 2:2. The meaning is, not that divisions are inseparable from the nature of the Christian religion, not that it is the design and wish of the Author of Christianity that they should exist, and not that they are physically impossible, for then they could not be the subject of blame; but that such is human nature, such are the corrupt passions of men, the propensity to ambition and strifes, that they are to be expected, and they serve the purpose of showing who are, and who are not, the…”

“There must be heresies - Divisions. Among you - In the ordinary course of things; and God permits them, that it may appear who among you are, and who are not, upright of heart. 1 Corinthians 11:20”

“11:19 As translated, this ironic expression rebukes the Corinthian Christians’ claims to superiority based on distinctions among them. Alternatively, Paul might be saying that though their divisiveness is clearly wrong, it will have the positive result of making clear who among them is truly faithful.”

“there: Mat 18:7; Luk 17:1; Act 20:30; Ti1 4:1, Ti1 4:2; Pe2 2:1, Pe2 2:2 heresies: or, sects, Act 5:17, Act 15:5, Act 24:5, Act 24:14, Act 26:5, Act 28:22; Gal 5:20; Tit 3:10 \*Gr. which: Deu 13:3; Luk 2:35; Co2 13:5-7 \*Gr: Jo1 2:19 1 Corinthians 11:20”