“Therefore,” what a great word. It signifies that a conclusion is being revealed on what has just been discussed. That’s the word Peter uses to signify that there is a course of action that is supposed to take place based on the information he has just discussed. The encouragement that Peter gives is to live a life that that is worthy of the salvation that they had already received.
His first point is for them to gird up the loins of their mind. This idea of girding up the loins refers to where people at this time would take the bottom of the robes and tuck them into their belt so they were able to move freely. Now the thought spoken of here by Peter is that they needed to get there minds in gear and prepare. Then he says be sober which means to be focused and aware and for them to rest their hope (expectations and desires) fully on the grace of Christ which would be revealed.
He then speaks in vs. 14 of things he wants them to do as obedient children. The desire of Peter is for them not to be put into the mold of the thought that the world has and that they had in their ignorance. But in contrast to that, he admonishes them to have holy thoughts. When Peter speaks of these thoughts he is contrasting holy thoughts with those of the world. Holy, by definition, is a setting apart where you would have the normal kind of thought within the world, holy thoughts are different. But, they are not just different, they are righteous as defined by the word of God. Peter in this text is saying: think as God would think.
One thing we must realize is that this is a directional command — this is a direction that we must work toward. Thinking and acting as God does not come overnight and it will take effort. So Peter as he sums up in vs. 16, quoting from Leviticus 11:44, he says, “Be Holy, for I am holy.” All of this leads us to the fact that we must strive to be like God in both thought and deed.
Then in vs. 17, we call upon our Father and we conduct ourselves throughout our time here with respect based on the fact that we have been redeemed. All of Peter’s discussion through these verses have been leading us to a kind of lifestyle that is worthy of Christ.