Matthew 5:48

Therefore ye shall be perfect; as your Father who is in heaven is perfect — So the original runs, referring to all that holiness which is described in the foregoing verses, which our Lord in the beginning of the chapter recommends as happiness, and in the close of it as perfection. And how wise and gracious is this, to sum up, and, as it were, seal all his commandments with a promise! Even the proper promise of the Gospel! That he will put those laws in our minds, and write them in our hearts! He well knew how ready our unbelief would be to cry out, this is impossible! And therefore stakes upon it all the power, truth, and faithfulness of him to whom all things are possible.