Having reminded the believers of their glorious corporate identity as the chosen people of God, whom He has acquired for His own possession (2:4-10), Peter then returns to the subject of how we are to conduct ourselves in this world, as sojourners and exiles on our way to our heavenly home. He reminds his readers (ref 1:14) that they are to abstain from the lusts of the flesh which controlled them while they were still in the world. These things, though pleasant to the senses, war against the health of the soul. They will affect our purity, fellowship, and usefulness in the service of the Lord.
Now when human authority commands us to disobey God, then we must obey God rather than man. We see examples in scripture when believers had to go against the command of the authorities, both religious and civil. Daniel continued to pray to Jehovah God, defying the edict of king Darius; Peter and John continued to preach Christ, defying the command of the religious rulers. Thankfully we are still free to worship and preach the gospel in this nation; but there may come a day when the gospel is considered hate speech; when that time comes, we must obey God rather than man.