Continue from Part 2
G. The obligations of the marriage covenant include at least  “leaving father and mother,”  “cleaving” to one’s spouse, and  becoming “one flesh.”
1. These three aspects of the marriage covenant are explicitly mentioned when God originally ordained the institution: “Therefore shall a man leave his father and his mother, and shall cleave unto his wife: and they shall be one flesh” (Gen. 2:24).
2. These three aspects of the marriage covenant are not distinctive to one dispensation of God’s dealing with men, but are repeated throughout Scripture: for instance, at Matthew 19:5 and Ephesians 5:31.
3. It may be that there are other integral aspects of the marriage covenant in addition to these three mentioned. To legitimately assert them would require Scriptural warrant of some sort (e.g., Biblical teaching on the essential meaning of marriage, or on accepted grounds for divorce, etc.).
H. In light of the vow to be “one flesh,” we can understand that sexual infidelity breaks the marriage covenant and is, as such, grounds for divorce.
1. The expression “to be one flesh” denotes sexual intercourse, thus being applied even to relations with a harlot: “Don’t you realize that he who is joined to a harlot is one body? for ‘the two,’ He said, ‘shall become one flesh'” (1 Cor. 6:16). Note how “marriage” is treated in parallel to “the bed” in Hebrews 13:4.
2. One of the divine purposes for marriage is to provide the proper outlet for the sex drive, thereby avoiding fornication: “Because of fornications, let each man have his own wife, and let each woman have her own husband…. It is better to marry than to burn (with passion)” (1 Cor. 7:2, 9). Outside of the marriage bed is fornication and adultery (Heb. 13:4).
3. Refusal of sexual relations is contrary to one of the very purposes for marriage, then, and illegally subjects the marriage partner to fornication – having a marriage, not in substance, but only in name.
4. Engaging in sexual relations is a “debt” which must be “paid (rendered)” to one’s spouse (1 Cor. 7:3; cf. the use of the same two words in Rom. 13:7, “render to all their dues”). It is a contractual obligation of marriage.
5. Willful refusal of sexual relations with one’s marriage partner is thus explicitly called “defrauding” (or stealing his/her rights) in 1 Corinthians 7:5. (The word is used of defrauding workers of the pay which is due to them in James 5:4; cf. Mark 10:19; 1 Cor. 6:8, referring to matters settled by court [vv. 1, 6].) It is a breaking of the contractual obligations of marriage. Paul’s use of this kind of language is noteworthy for understanding the covenantal nature of the marriage bond as well as how it is dissolved.
6. This is confirmed by the law at Exodus 21:10-11, which stipulates that a wife who has been deprived of “her conjugal right” becomes free of the marriage commitment, being released from her husband. (It would make little sense to say that “she shall go out from him” pertains only to her slavery, leaving her bound to the marriage, when it is her conjugal rights [which have nothing to do with the institution of slavery] that are not being observed.)
7. Since the marriage vow is (among other things) a public commitment to be sexually faithful to one’s spouse, sexual relations apart from with one’s spouse is a violation of the marriage covenant. Thus, as is commonly recognized, Scripture teaches that when a wife commits adultery, she may be put away and given a bill of divorcement (Jer. 3:8; cf. Deut. 24:1, noting that the Hebrew term “indecency” refers to illicit cohabitation, e.g., Ezek. 16:36; 23:29; throughout Lev. 18; 20:10ff.). Adultery “defiles” the marriage bed (Heb. 13:4).
Author Greg Bahnsen