“seven pairs.” The Hebrew text of Genesis 7:2 simply repeats the number seven twice, and literally reads, “seven seven,” which in this context means “seven pairs” (cp. CJB; HCSB; NAB; NIV2011; NJB; NLT; NRSV; RSV). What the “seven seven” means is clarified by the words that follow. The Hebrew text reads more literally, “seven seven, a male and his mate.” So Genesis 7:2 should be understood to mean “seven males, seven females; a male and his mate.” Thus, there were to be seven males and seven females of each clean animal on the ark. There were also to be seven pairs of the different kinds of birds on the ark (Gen. 7:3). The tradition that the animals went on only in twos comes from misunderstanding Genesis 6:19, which says that “two” of each animal was put on the ark, but in that context, the word “two” refers to “pairs,” not just “two” animals. See commentary on Genesis 6:19, “pairs.” The fact that there were seven pairs of clean animals and birds on the ark also explains how Noah could get off the ark and sacrifice some of the clean animals and birds and still have animals and birds to reproduce the species (Gen. 8:20).