Marriage is a covenant (Prov. 2:16-17; Mal. 2:14).
It is defined as a sacred bond between a man and a woman established by and publicly entered into before God; as “an agreement that a faithful person would not break even if the partner to whom that person is in covenant breaks the stipulations of the covenant.” While there are various types of covenants established in Old Testament times (e.g., Noahic, Abrahamic, Mosaic, Davidic, and New Covenant) between God and human beings, between humans, and for marriage (Prov. 2:17; Ezek. 16:8; Mal. 2:14), the term “covenant” in general conveys, “the idea of a solemn commitment, guaranteeing promises or obligations undertaken by one or both covenants and parties.”
In the Old Testament salvation was found only in God, based on him fulfilling the covenant, not on the people’s obedience. God says in Leviticus, “You reject My statutes, and if your soul abhors My ordinances so as not to carry out all My commandments, and so break My covenant…[I will punish you]…Yet in spite of this, when they are in the land of their enemies, I will not reject them, nor will I so abhor them as to destroy them, breaking My covenant with them; for I am the LORD their God” (Lev. 26:15, 44, NIV, addition added), because, “I will never break My covenant with you” (Judges 2:1, NIV). Old and new covenants have always been solely foundational on God’s hesed love; spiritual apostasy in the Old Testament was no more dependent on human’s obedience; than in the New Testament (Eph. 2:8-9).
Professor and author, Dr. Daniel Heimbach explains that the marriage covenant is a relationship between three parties: God, a husband, and a wife. A covenant is not primarily a legal bond, but is spiritual and moral bond; and God holds us accountable regardless of what human authorities may allow (i.e., legal certificate of divorce). The Bible never treats adultery as a matter of violating property rights, but always as a moral issue. That is why the Seventh Commandment is separate from the Eighth. The sanctions regarding the sanctity of sex and marriage are the same as regarding the sanctity of human life. In the Old Testament the punishment for adultery was death (Deut. 22:22), the same as for murder; however the punishment for fornication (consensual sex between unmarried) was not as severe—not death, but mandatory marriage and a fine (Deut, 22:28-29)—most likely because it does not violate the sanctity of the marriage covenant.
In the New Covenant, in Christ—the “holy nation” and “royal priesthood” are called to a more challenging standard than ever before. Jesus calls his followers to deny themselves (Matt. 16:24; Mk. 8:34; Lk. 9:23), their pursuit of happiness on selfish terms, and fulfilling their own personal desires (Jas. 4). Based on the biblical promise that true believers are never lost from Christ (Rom. 8:38-39) and this life is for God’s glory, not our final resting place (1 Tim. 4:10; Phil 3). The marriage covenant—though not exact—is one of the most beautiful displays of God’s unconditional covenant with His people. The New Covenant established by Christ with his church, in the mind of the Paul (Eph. 5:22-33) was a permanent relationship created by a redemptive act of love when Christ “gave himself up for it he might sanctify, having cleansed it by the washing of water with the word, it he might present the church to himself a glorious church. "This is the model marriage is to form after, even though imperfect at times.