1A. Because of the command of Christ:
Matthew 28:19-20; Mark 16:15 (cf. John 14:15).
2A. Because of the condition of all men:
Matthew 9:36-38; 13:49-50; II Thessalonians 1:7-10; I Peter 4:17-18; Jude 23; Revelation 20:15.
3A. Because of the consequences of the gospel:
Matthew 7:13; 14: 49-50; II Thessalonians 1:7-10; I Peter 4:17-18; Jude 23; Revelation 20:15.
4A. Because of the coming of Christ:
I Corinthians 15:58; II Corinthians 5:10-11; I Thessalonians 2:19-20.
5A. Because of the constraint of love:
II Corinthians 5:14 (cf. Paul's example in Romans 9:1-3; 10-1).
6A. Because of the character of the gospel: It is the only thing that works!
Acts 4:12; Romans 1:14-16
7A. Because of the commitment of the message to us:
I Corinthians 9:16-23; II Corinthians 5:18-20; I Thessalonians 2:4-8; I Timothy 1:11-16.
1C. Isolation: avoiding all association and contact with unbelievers for fear of contamination.
2C. Compromise: adapting to secular culture to the point of sinful practices and questionable behavior.
3C. Separation: approaching unbelievers within their cultural framework, but maintaining moral purity (cf. II Corinthians 6:14-7:1; I Corinthians 5:9-11; 9:19-22).