There is nothing finished that we do: all our duties are imperfect duties; they come off lamely, and defectively from our hands… O there is much impudence and vanity in the best of our duties: but here is the grand relief, and that which answers to all the grounds of our doubts and fears upon that account; Jesus Christ hath finished all His work, though we can finish none of ours: and so, though we be defective, poor, imperfect creatures, in ourselves, yet, notwithstanding, we are complete in Him (Colossians 2: 9, 10)… Christ’s complete obedience being imputed to us, makes us complete, and without fault before God.

It is true, we ought to be humbled for our defects, and troubled for every failing in obedience; but we should not be discouraged, though multitudes of weaknesses be upon us, and many infirmities compass us about, in every duty we put our hand to; though we have no righteousness of our own; yet of God, Christ is made unto us righteousness; and that righteousness of His is infinitely better than our own…

John Flavel, Sermon XXXV, The Fountain of Life, Works, Volume 1, pages 436-437.