1 Thessalonians 3:13

To the end he may stablish your hearts unblameable in holiness before God, even our Father, at the coming of our Lord Jesus Christ with all his saints.

Your hearts - naturally the spring of unholiness.

Before God, even our Father - rather, 'before Him who is at once God and our Father.' Before not merely men, but Him who is not deceived by the show of holiness - i:e., may your holiness be such as will stand his scrutiny. God will judge by Christ (2 Corinthians 5:10; Acts 17:31).

Coming, [ parousia (G3952)] - 'personal presence.'

With all his saints - including holy angels, and the holy elect of men (1 Thessalonians 4:14; Daniel 7:10; Zechariah 14:5; Matthew 15:31; 2 Thessalonians 1:7). The saints are "His" (Acts 4:13). We must have "holiness" if we are to be numbered with His holy one. [ Hagiotees (G41) is holiness in the abstract. Hagiosunee is the state of holiness: hagiasmos (G38), the process of being made holy.] On "unblameable," cf. Revelation 14:5. This verse (cf. with 1 Thessalonians 3:12) shows "love" is the spring of "holiness" (Matthew 5:44-40; Romans 13:10; Colossians 3:14). God really "stablishes;" Timothy and others are but instruments (1 Thessalonians 3:2) in 'stablishing.'