Reconciliation through the Blood of the Cross
Therefore we have another and wholly distinct step - 'by him to reconcile all things unto himself.'
All the fullness dwelling in Him was insufficient; it brought God to man, not man to God. All the Godhead was pleased to dwell in Him, and not as a mere passing thing. This was quite independent of the anointing in due time by the Holy Ghost. It was the continual delight of the whole Godhead to dwell in Him as man.
But so far gone was man that this could not deliver him; sin cannot be thus got over. Even God Himself coming down to earth in Christ's Person, His unselfish goodness, His unwearied patient love, not anything found in Christ nor all together, could dispel sin or righteously recover the sinner.
Therefore it became manifestly a question of reconciliation 'through the blood of his cross.'
(taken from William Kelly's commentary on Colossians 1:19,20)