Genesis 38:3
She became pregnant and had a son. Judah named him Er.
Genesis 46:12
The sons of Judah: Er, Onan, Shelah, Perez, and Zerah (but Er and Onan died in the land of Canaan). The sons of Perez were Hezron and Hamul.
Numbers 26:19
The descendants of Judah were Er and Onan, but Er and Onan died in the land of Canaan.
Treasury of Scripture Knowledge
Summary
And she conceived, and bare a son; and he called his name Er.
Bible References
Er
Genesis 46:12
The sons of Judah: Er, Onan, Shelah, Perez, and Zerah (but Er and Onan died in the land of Canaan). The sons of Perez were Hezron and Hamul.
Numbers 26:19
The descendants of Judah were Er and Onan, but Er and Onan died in the land of Canaan.