Apostolic Constitutions : But do you, brethren, who are instructed out of the Scripture, take care not to make divisions in opinion, nor divisions in unity. For those who set up unlawful opinions are marks of perdition to the people. In like manner, do not you of the laity come near to such as advance doctrines contrary to the mind of God; nor be you partakers of their impiety. For says God: "Separate yourselves from the midst of these men, lest you perish together with them." And again: "Depart from the midst of them, and separate yourselves, says the Lord, and touch not the unclean thing, and I will receive you." — Constitutions of the Holy Apostles Book 6 Clement of Alexandria : Wherefore also in the Barbarian philosophy they call those dead who have fallen away from the dogmas, and have placed the mind in subjection to carnal passions. "For what fellowship hath righteousness and iniquity?" according to the divine apostle. "Or what communion hath light with darkness? or what concord hath Christ with Belial? or what portion hath the believer with the unbeliever?" For the honours of the Olympians and of mortals lie apart. "Wherefore also go forth from the midst of them, and be separated, saith the Lord, and touch not the unclean thing; and I will receive you, and will be to you for a Father, and ye shall be my sons and daughters." — The Stromata Book 5 John Chrysostom : "Wherefore come ye out from among them, and be ye separate, and touch no unclean thing; and I will receive you, saith the Lord." And He said not, 'Do not unclean things'; but, requiring greater strictness, 'do not even touch,' saith he, 'nor go near them.' But what is filthiness of the flesh? Adultery, fornication, lasciviousness of every kind. And what of the soul? Unclean thoughts, as gazing with unchaste eyes, malice, deceits, and whatsoever such things there be. He wishes then that they should be clean in both. Seest thou how great the prize? To be delivered from what is evil, to be made one with God. — Homily 13 on 2 Corinthians Tertullian : Again, "Go ye out from the midst of them; touch not the unclean thing; separate yourselves, ye that bear the vessels of the Lord." (The apostle says further: ) "Be not drunk with wine, wherein is excess," -a precept which is suggested by the passage (of the prophet), where the seducers of the consecrated (Nazarites) to drunkenness are rebuked: "Ye gave wine to my holy ones to drink. — Against Marcion Book V Tertullian : If you think this said about a heathen, at all events about believers you have already heard (it said) through Isaiah: "Go out from the midst of them, and be separate, and touch not the impure." You have at the very outset of the Psalms, "Blessed the man who hath not gone astray in the counsel of the impious, nor stood in the way of sinners, and sat in the state-chair of pestilence; " whose voice, withal, (is heard) subsequently: "I have not sat with the conclave of vanity; and with them who act iniquitously will I not enter"-this (has to do with "the church" of such as act ill-"and with the impious will I not sit; " and, "I will wash with the innocent mine hands, and Thine altar will I surround, Lord" -as being" a host in himself"-inasmuch as indeed "With an holy (man), holy Thou wilt be; and with an innocent man, innocent Thou wilt be; and with an elect, elect Thou wilt be; and with a perverse, perverse Thou wilt be. — On Modesty