XIII. It would likewise be false to infer from this, that “if Christ performed obedience for us, we ourselves are under no necessity of obeying, because no demand can be made on the principal debtor, for what the surety has performed in his room.” Our obedience may be considered, either as it is the duty of the rational creature, with respect to his sovereign Lord; or as it is a condition of acquiring a right to eternal life: in the latter respect Christ accomplished it for us; and therefore, under that relation, it neither is nor can be required of us, as if for want of perfect obedience we could be excluded from eternal life. But in the former respect, we by all means owe obedience, and the obligation to it is rather increased than diminished by this instance of Christ’s love. For what more proper, than by this to show our gratitude, and declare, not so much by words as actions, that we acknowledge him for our Lord, who has purchased us for himself? And in fine, that as adopted sons we decline no obedience to our heavenly Father, whom his natural Son, and of the same substance with himself, so cheerfully obeyed.
Witsius, Herman (2014-08-21). Economy of the Covenants Between God and Man, 2 Vols. (Kindle Locations 3432-3439). . Kindle Edition.