1 Peter 4:17-18
17 For the time is come that judgment must begin at the house of God: and if it first begin at us, what shall the end be of them that obey not the gospel of God?
18 And if the righteous scarcely be saved, where shall the ungodly and the sinner appear?
The Grace New Testament Commentary - 1 Peter 4:18
4:18 Peter now quotes Prov 11:31 to affirm the certainty of the judgment of the wicked. This brings up the point of v 15 - what not to suffer for! God will not let His children get away with sin. And if He will not let them get away with anything ("scarcely saved"), the "ungodly" do not have a chance.