1 Peter 1:16

because it is written, Be ye holy, for I am holy.

Because the believers are kept by the power of God through faith unto salvation, therefore there is need that they be strengthened in faith and a holy life day by day, as the apostle writes: Therefore, girded up in the loins of your mind and with soberness of spirit, set your hope definitely upon the grace which is being brought to you in the revelation of Jesus Christ. The picture is that of a person who is altogether ready for a journey or for a piece of work in the performance of which he wants to be unhindered, with no loose garments impeding his progress by wrapping themselves about his limbs. The mind of the Christians must ever be alert, full of intent watchfulness, ready for the business of the Master, and sober, not engaged in the lusts and desires of the world. Their minds must be directed exclusively toward Christ and toward the goal which they have set before them. In this condition, in this state of mind, Christians should set their hope definitely, without wavering, without the slightest indication of uncertainty, upon the grace of God as it is set before us again and again in the revelation of Jesus Christ, upon the future salvation which God gives to us out of pure grace and mercy. When Christ will be revealed to our eager eyes on the last day, it will be for the purpose of putting us, the elect sojourners here on earth, into the possession of our heavenly inheritance. This we know; and therefore our hope is so sure, so steadfast.

The apostle now shows what attitude, what conduct agrees with the hope of the future grace: As children of obedience, not molding yourselves after the former lusts in your ignorance. Christians must at all times show themselves children of obedience; that is the sphere in which they should be found, in obedience to the gracious will of God, to the Gospel. For this reason they will avoid everything that might endanger their chances of salvation. They will not fashion themselves, they will not mold their opinion, their conduct, according to the lusts and desires which formerly, while they were still in ignorance of the holy will of God, ruled in them. Every unconverted person, every heathen, knows no better than to seek his fortune, his happiness, the gratification of his ambitions in doing after the lusts of his heart. All this the believers have renounced, with all this they have nothing in common any more.

The thought which governs the life of the Christians is this: But as He that called you is holy, so be also you holy in your entire conduct; for it is written, You shall be holy, for I am holy. God is the absolutely Pure and Holy One; in Him is no darkness, but He is light. It is He that has called the Christians by the Gospel, converting them to faith in Jesus Christ, their Savior. In accordance with this call, therefore, and with the fact that it is the Holy One that issued the call, the Christians should likewise prove themselves holy, striving in their whole life and conduct after the purity, the righteousness, which is well-pleasing to Him. Instead of bearing in their attitude the form of evil lusts, they should be renewed to the image of God. This is the will of God, as He Himself has stated in His Word, Leviticus 11:44; Leviticus 19:2; Leviticus 20:26. That is the unchangeable will of God with reference to His children, that they make the holiness which He has in His essence their ideal, that the hope and the faith of their hearts find its expression in the sanctification of their lives, Colossians 1:12; Hebrews 12:14.