And this obedience is the next precept for which they are to be made ready by the girding up of the loins of their minds, _as children of obedience_, the obedience not of slaves, but of sons. Children they are become by virtue of the new birth, and obedience it is which gives them a claim upon God's Fatherhood. They must seek for the docility and trustfulness of the childlike character; they must accept a law other than their own wills, having taken upon them the yoke of Christ and aiming, in the light of His example, to become worthy of being reckoned among His true followers.
When they contemplate their own lives, they must feel that a mighty change is needed from what they were aforetime. St. Peter's words mark the completeness of the needed change: _not fashioning yourselves according to your former lusts_. In time past they had sought no further for a guide and pattern than their own perverted desires; now they must school themselves to say, "Do with me as Thou wilt, for I am Thine." And He whose grace has begotten them again will help them to frame their lives by His rule, will have them learn of Him. But while the Apostle dwells on the difference which must come over the lives of these converts, mark the wondrous charity with which he alludes to their former life in error. _In the time of your ignorance_, he says. Even here he follows the example of the Lord, who prayed in His agony, "Father, forgive them, for they know not what they do." Sin blinds the moral and the mental vision too, and men so blinded sink deeper and deeper into the slough, while he who has learnt Christ has gained another source of light. But, to raise the ignorant, they must be taught; and tenderness makes teaching most effective, and charity dictates the apostolic words. So St. Paul at Athens to those who worshipped an unknown God offered instruction to win them from their ignorance, and pointed them to a God whose offspring they were, and to whose likeness they might be conformed.
Just so does St. Peter; _Like as He who called you is holy, be ye yourselves also holy in all manner of living_. This has been God's call from the first day until now, but what a hopeless height is this for the sinner to aim after, holy as God is holy! Yet it is the standard which Christ sets before us in the Sermon on the Mount: "Be ye perfect, even as your Father which is in heaven is perfect." And why does He propose to us that which is impossible? Because with the command He is ready to supply the power. He knows our frailty; knows what is in man both of strength and weakness. At the same time He proclaims to us by this command what God intends to make of us. He will restore us again to His own likeness. That which was God's at first shall be made God's once more. The marred image, on which not even the superscription can be traced, shall again be revealed in full clearness, and the believer purged from all the defilements of sin by the grace and help of Him who says, "Be ye perfect," because He loves to make us so.
_Because it is written, Ye shall be holy; for I am holy._ This command comes down to us from the earliest days of the Law. But in those old times it could not be said, _in all manner of living_. These words betoken the loftier standard of the New Testament. The patriarchs and prophets and the people among whom they lived were trained, and could only be trained, little by little. Even in the best among them we cannot hope for holiness in all manner of living. It was only by the types and figures of external purification that their thoughts were directed to the inner cleansing of the heart, and long generations passed before the lessons were learnt. The full sense of the Fatherhood of God was not attained under the Law, nor did men under it learn fully to live as children of obedience, children of a Father who loves and will succour every effort which they make to walk according to His law. The Incarnation has brought God nearer to man, and on this relationship of love the Apostle grounds his further exhortation.