It seems proper, in the mean time, to remark that, amongst the various acts of faith which we are about to describe, there is one which holds the principal place, and in which, as it unites us to Christ and justifies us, we apprehend the essence and formal nature of faith to consist. This must be carefully attended to, particularly in the matter of justification; lest several expressions of love which, in different ways, are involved in the exercise of faith, should be rashly numbered among the causes of our justification.
Herman Witsius, Sacred Dissertations on the Apostles’ Creed, 1.37. (HT: Gil Garcia)
Our imperfect obedience, expressed as love to God and our fellow man, must never be seen as contributing anything to our justification. To do so is to fail to submit to the righteousness of God. It is to fail to trust in Christ alone. It is to return to the law for our righteousness. Our flawed obedience is fruit and evidence that the Holy Spirit is sanctifying us and gradually conforming us to the image of Christ to be fully realized at the resurrection. It is all of grace alone.