When a person becomes a believer but his spouse does not, the question of the believer’s remaining in the marriage arises (v. 12). The unbelieving spouse may consent to remain in the marriage, allowing the believer to practice his new Christian faith. In this situation, the believer is not to separate or seek a divorce but is to remain married as long as the unbeliever desires to remain married (vv. 12–13). The faith of the believing spouse means that the unbelieving spouse is set apart or made holy for God’s purposes: “Otherwise your children would be unclean, but as it is, they are holy” (v. 14).
God’s promises of salvation, which began in Genesis 3:15, come to expression in the form of a gracious covenant in which the Lord, on His own initiative, commits Himself to be Abraham’s God and the God of his children (Gen. 17:7). This is a staggering total commitment to a sinful man whose background was in idolatry (Josh. 24:2–3). Naturally, there are obligations in response (Gen. 17:1). In the New Testament, the extent of the Lord’s total commitment is seen in God’s not sparing His Son, His only Son, whom He loves, for our redemption in an act that far transcends the binding of Isaac (ch. 22). Christ’s sacrifice ratifies the new covenant, which is new in form but not in essence. Paul affirms, “If you are Christ’s, then you are Abraham’s offspring, and heirs according to promise” (Gal. 3:29).
In his sermon on the day of Pentecost, Peter states, “The promise is for you and for your children and for all who are far off” (Acts 2:39)—for both Jew and gentile. The nation of Israel, consisting of professing believers and their children, is called a holy nation (Ex. 19:5–6; Deut. 14:1–2), just as is the church in the New Testament (1 Peter 2:9). Not all members of the old covenant community were regenerate and converted. Warnings about Israel’s incurring God’s curse through disobedience abound: “Not all who are descended from Israel belong to Israel” (Rom. 9:6), even if as natural branches they remain holy in some sense (11:16). The church, too, may have those who fall away. They were grafted in through profession of faith but are cut off by unbelief and will not enter God’s rest (Heb. 4:11).
Thus, covenantal holiness describes the relationship of being in God’s covenant family even when the aim of the relationship in a vital communion with God through Christ by the Spirit is not realized.