As the U.S. Supreme Court deliberates on its definition of marriage this week, remember that Christians must stand, unashamedly, upon the Word of God. Genesis defines marriage as procreative in nature (1:28, which necessarily excludes homosexual unions) and as being exclusively between one man and one woman (2:24). The book of Genesis also describes the sin of Sodom and Gomorrah as "very grave" (18:20). The book of Leviticus says that homosexuality is an "abomination" (18:22)