Parallel
Genesis 38:9
Clementine Vulgate · Berean Standard Bible
Ille sciens non sibi nasci filios, introiens ad uxorem fratris sui, semen fundebat in terram, ne liberi fratris nomine nascerentur.
But Onan knew that the offspring would not belong to him; so whenever he would sleep with his brother’s wife, he would spill his seed on the ground so that he would not produce offspring for his brother.