Genesis 38:8-10

Expanded Bible

⁸ Then Judah said to Er’s brother Onan, “Go and have sexual relations with your dead brother’s wife. It is your duty to ·provide children for your brother in this way [^Lraise up a seed for your brother; Deut. 25:5–10].”

⁹ But Onan knew that the ·children [^Lseed] would not belong to him, so when he ·was supposed to have sexual relations with [^Lhe went to] Tamar he ·did not complete the sex act [^Lspilled his seed on the ground], ·making it impossible for Tamar to become pregnant and for Er to have descendants [^Lso that he did not give a descendant/seed to his brother]. ¹⁰ ·The Lord was displeased by this wicked thing Onan had done [^LWhat he did was evil in the eyes/sight of the Lord], so he killed Onan also.