9 and Onan knoweth that the seed is not [reckoned] his; and it hath come to pass, if he hath gone in unto his brother's wife, that he hath destroyed [it] to the earth, so as not to give seed to his brother;
9
But Onan knew that the child would not be his; so whenever he slept with his brother’s wife, he spilled his semen on the ground to keep from providing offspring for his brother.
Young's Literal Translation is in the public domain.