The root of the words pitch in this verse and expiation elsewhere in the Old Testament means primarily to cover. The pitch here is a type of the redeeming blood of Christ, which covers God’s building within and without (Lev. 4:5-7; 6:30; 16:14-19; Heb. 9:21). The pitch within the ark was for the peace of Noah and his family (cf. Heb. 9:14), whereas the pitch without was for God’s satisfaction (cf. Exo. 12:13). Noah and his family were saved from the judgment of the flood by the pitch on the ark, signifying that the believers in Christ are saved from God’s judgment by the redeeming blood of Christ (Rom. 5:9).
In order for the pitch on the ark to be effective, Noah and his family had to be in the ark, i.e., in union with the ark. Likewise, in order to apply the redemption through Christ’s blood, we must be in Christ, i.e., in union with Him by believing into Him (John 3:16; 1 Cor. 1:30; Eph. 1:7). See note Gen. 3:212a, note Exo. 12:222, and note 1 John 2:22.