KJV: And Judah said unto Onan, Go in unto thy brother's wife, and marry her, and raise up seed to thy brother.
NASB: Then Judah said to Onan, "Go in to your brother's wife, and perform your duty as a brother-in-law to her, and raise up offspring for your brother."
KJV: And Onan knew that the seed should not be his; and it came to pass, when he went in unto his brother's wife, that he spilled it on the ground, lest that he should give seed to his brother.
NASB: Onan knew that the offspring would not be his; so when he went in to his brother's wife, he wasted his seed on the ground in order not to give offspring to his brother.
KJV: And the sons of Judah; Er, and Onan, and Shelah, and Pharez, and Zerah: but Er and Onan died in the land of Canaan. And the sons of Pharez were Hezron and Hamul.
NASB: The sons of Judah: Er and Onan and Shelah and Perez and Zerah (but Er and Onan died in the land of Canaan). And the sons of Perez were Hezron and Hamul.
KJV: The sons of Judah; Er, and Onan, and Shelah: which three were born unto him of the daughter of Shua the Canaanitess. And Er, the firstborn of Judah, was evil in the sight of the LORD; and he slew him.
NASB: The sons of Judah were Er, Onan and Shelah; these three were born to him by Bath-shua the Canaanitess. And Er, Judah's firstborn, was wicked in the sight of the LORD, so He put him to death.