Jamieson, Fausset and Brown on Colossians 2:6

6. "As therefore ye received (once for all; the aorist tense; from Epaphras) Jesus the Christ as your Lord (compare 1Co 12:3; 2Co 4:5; Php 3:8), so walk in Him." He says not merely, "Ye received" the doctrine of Christ, but "Jesus" Himself; this is the essence of faith (Joh 14:21, 23; Ga 1:16). Ye have received once for all the Spirit of life in Christ; carry into practice that life in your walk (Ga 5:25). This is the main scope of the Epistle.