And Onan knew that the seed should not be his; and it came to pass, when he went in unto his brother’s wife, that he spilled [it] on the ground, lest that he should give seed to his brother.
Jewish Publication Society of America Version (JPS1917) - Genesis 38:9 >And Onan knew that the seed would not be his; and it came to pass when he went in unto his brother's wife, that he spilled it on the ground, lest he should give seed to his brother.