Judah's sons are the descendants of Judah, one of the twelve tribes of Israel. Judah had three sons: Er, Onan, and Shelah. According to the biblical narrative in the book of Genesis, Er was the firstborn, but he died young due to his wickedness. Onan was then instructed to marry Er's widow, Tamar, but he also died after refusing to fulfill his duty. Tamar later deceived Judah to ensure her lineage continued, leading to the birth of twins, Perez and Zerah. Perez became an important ancestor in the lineage of King David and, ultimately, Jesus in the New Testament.