“In Romans 16:7 Paul mentions those who ‘were in Christ before me’ or ‘before I was.’ Here Paul, speaking autobiographically but surely representatively of all Christians, brings into view a before and after of being ‘in Christ’ that points to a critical transition.” (Richard B. Gaffin, Jr., By Faith, Not By Sight, p. 37).
“We may not tone down the unity of the church. This comes to expression repeatedly in Paul (cf. 11:16-24; Eph. 2:16, 18-22; 4:2-16). But Paul is also jealous to maintain that in every instance where the saints are gathered together in Christ’s name in accordance with his institution, there the church of Christ is (cf. vs.5).” (John Murray, The Epistle to the Romans, Vol. 2, p. 233).