1Peter 1:16 “Because it is written, Be ye holy; for I am holy.”
But as he who hath called you, etc., v. 15, 16. Here is a noble rule enforced by strong arguments: Be you holy in all manner of conversation. Who is sufficient for this? And yet it is required in strong terms, and enforced by three reasons, taken from the grace of God in calling us,-from his command, it is written,-and from his example. Be you holy, for I am holy. Learn,
(1.) The grace of God in calling a sinner is a powerful engagement to holiness. It is a great favour to be called effectually by divine grace out of a state of sin and misery into the possession of all the blessings of the new covenant; and great favours are strong obligations; they enable as well as oblige to be holy.
(2.) Complete holiness is the desire and duty of every Christian. Here is a two-fold rule of holiness: [1.] It must, for the extent of it, be universal. We must be holy, and be so in all manner of conversation; in all civil and religious affairs, in every condition, prosperous or reverse; towards all people, friends and enemies; in all our intercourse and business still we must be holy. [2.] For the pattern of it. We must be holy, as God is holy: we must imitate him, though we can never equal him. He is perfectly, unchangeably, and eternally holy; and we should aspire after such a state. The consideration of the holiness of God should oblige as to the highest degree of holiness we can attain unto.
(3.) The written word of God is the surest rule of a Christian’s life, and by this rule we are commanded to be holy every way. (4.) The Old-Testament commands are to be studied and obeyed in the times of the New Testament; the apostle, by virtue of a command delivered several times by Moses, requires holiness in all Christians.
– Matthew Henry