This text ranks as one of the most difficult to understand and explain in all of the New Testament. Yet overall the point is clear: those who suffer for righteousness, like Noah, must recognize that God has not forsaken them, but will both save them from the judgment they deserve and from the enemies that surround them.
For Noah, the means of rescue were the Ark and the water. For Christ-followers today the means of rescue is Christ, through His death and resurrection that is radically symbolized and impressed upon our hearts through the act of baptism.
Peter reminds his readers that even as Noah was brought to safety through water, so also do the waters of baptism symbolize our salvation through Jesus Christ, who now is at God’s right hand, with all power and authority subject to Him.