Matthew 5:48

Jesus Christ here sums up his instructions by ordering us to be perfect as our heavenly Father is perfect; i.e. to imitate, as far as our exertions, assisted by divine grace, can reach, the divine perfection. (Witham) --- See here the great superiority of the new over the old law. But let no one hence take occasion to despise the old. Let him examine attentively, says St. John Chrysostom, the different periods of time, and the persons to whom it was given; and he will admire the wisdom of the divine Legislator, and clearly perceive that it is one and the same Lord, and that each law was to the great advantage of mankind, and wisely adapted to the times of their promulgation. For, if among the first principles of rectitude, these sublime and eminent truths had been found, perhaps neither these, nor the less perfect rules of mortality would have been observed; whereas, by disposing of both in their proper time, the divine wisdom has employed both for the correction of the world. Hom xviii. Seeing then that we are thus blessed as to be called, and to be the children of so excellent a Father, we should endeavour, like Him, to excel in goodness, meekness, and charity; but above all in humility, which will secure to us the merit of good works, through the infinite merits of our divine Redeemer, Master, and model, Christ Jesus the Lord. (Haydock)