We then, as workers together with him, beseech you also that ye receive not the grace of God in vain. We then, as workers together with him, beseech you also that ye receive not the grace of God in vain.
Workers together - with God (Acts 15:4; 1 Corinthians 3:9). Not only as "ambassadors" He is describing his ministry, not exhorting directly.
You also - rather, 'we ALSO (as well as God, 2 Corinthians 5:20) х parakaloumen (G3870), 2 Corinthians 5:20] plead with you:' 2 Corinthians 6:14-15, on to 2 Corinthians 7:1, is part of this entreaty.
In vain - by making the grace of God a ground for continuance in sin (2 Corinthians 6:3). A life of sin makes the word of reconciliation vain, so far as the sinner is concerned (Hebrews 12:15; Jude 1:4). "The grace of God" is the "reconciliation" provided by God's love (2 Corinthians 5:18-19: cf. Galatians 2:2).