What is the meaning of Leviticus 18:18? You must not take your wife’s sister - The command immediately limits a husband’s choices, rooting marriage in exclusive commitment. Genesis 2:24 says, “For this reason a man will leave his father and mother and be united to his wife, and they will become one flesh,” reinforcing that God’s design is one man and one woman forming a single-flesh union. - Other laws echo the boundary: “You are not to uncover the nakedness of your sister-in-law” (Leviticus 18:16); “You shall not commit adultery” (Exodus 20:14). - The direction also guards family harmony, preventing the confusion and pain that spring from overlapping loyalties (cf. Proverbs 5:18–19). as a rival wife - Scripture highlights the turmoil of competing spouses; Jacob’s household became “filled with jealousy” (Genesis 29:30–31), and Elkanah’s wives discouraged one another (1 Samuel 1:6). - God’s wisdom counters rivalry: “Where jealousy and selfish ambition exist, there is disorder” (James 3:16). A marriage designed for unity cannot thrive when rivalry intrudes. and have sexual relations with her - Sexual intimacy belongs inside the covenant of one-flesh marriage. “Marriage is to be honored by all and the marriage bed kept undefiled” (Hebrews 13:4). - Paul urges, “Flee from sexual immorality” (1 Corinthians 6:18), a call that covers both premarital and extra-marital activity. - Violating this boundary carried severe consequences in Israel: “If a man marries a woman and her mother, all three must be burned with fire” (Leviticus 20:14). Though that verse addresses mother-daughter relations, it underscores how gravely God views sexual sin within a family circle. while your wife is still alive - The phrase affirms the lifelong covenant until death parts a couple. “A married woman is bound by law to her husband while he lives” (Romans 7:2). - Jesus echoed Genesis when He said, “So they are no longer two, but one flesh. Therefore what God has joined together, let man not separate” (Mark 10:8–9). - Malachi 2:14–16 portrays God as witness to marriage vows and denounces treachery against “the wife of your youth,” stressing faithfulness as long as both live. summary Leviticus 18:18 draws a clear fence around marriage: no husband may add his wife’s sister to the household in a polygamous, competitive, or sexual way while his wife lives. The verse safeguards the sanctity of the original one-flesh bond, prevents rivalries that fracture families, and upholds God’s lifelong design for marriage—a principle echoed throughout Scripture from Genesis to Jesus’ own teaching. |
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