a man shall: This is to be understood as referring to the case of a stepmother. A man in his old age may have married a young woman, and on his dying, his son by another, or a former wife, may desire to espouse her; which is here forbidden. Deuteronomy 27:20; Leviticus 18:8, Leviticus 20:11; 1 Corinthians 5:1, 1 Corinthians 5:13
discover: Ruth 3:9; Ezekiel 16:8