This custom Christ also observed, and commanded that the disobedient in the church should be so regarded, saying: “If he neglect to hear the church, let him be unto thee as a heathen man and a publican.” Matt. 18:17.
This the apostles also practiced in like manner, according to the doctrine of Christ. Read: “I wrote unto you in an epistle not to company with fornicators: yet not altogether with the fornicators of this world, or with the covetous, or extortioners, or with idolaters; for then must ye needs go out of the world. But now I have written unto you not to keep company, if any man that is called a brother be a fornicator, or covetous, or an idolater, or a railer, or a drunkard, or an extortioner; with such a one no not to eat.” 1 Cor. 5:9–11.
Here the holy apostle forbids us to company and eat with apostate brethren or sisters, which he did not mean or command with reference to the unrighteous of this world, but permitted it with them; else we would needs have to go out of the world, seeing the whole world lies in wickedness; hence it must necessarily be understood with reference to daily intercourse and eating, buying and selling, and the like. “A man that is a lunatic, after the first and second admonition, reject.” Titus 3:10; 2 Tim. 4:15; 2 John 10.
“And if any man obey not our word by this epistle, note that man, and have no company with him, that he may be ashamed.” 2 Thess. 3:14.
How this withdrawing is to be observed by all believers, with regard to all apostates, walking disorderly, without respect of person, read: “Now, we command you, brethren, in the name of our Lord Jesus Christ, that ye withdraw yourselves from every brother that walketh disorderly, and not after the tradition which he received of us.” 2 Thess. 3:6.
Understand this withdrawing according to scriptures. Gal. 2:12; 3 Macc. 2:34, and the like, according to the spirit of the Gospel of Christ.
How believers must seek the lost, and not count the separated as enemies, but admonish them, as brethren. Read: 2 Thessalonians 3:15; Jas. 5:19; Luke 19:10; 15, the whole chapter.