These are the names of the mighty men whom David had: Josheb-basshebeth a Tahchemonite; he was chief of the three. He wielded his spear against eight hundred whom he killed at one time
2 Samuel 23:8
This is an account of David’s mighty men: Jashobeam, a Hachmonite, was chief of the three. He wielded his spear against 300 whom he killed at one time.
1 Chronicles 11:11
The Claim: How many men did he kill? 2 Samuel says it was 800, while 1 Chronicles says it was 300. That’s a contradiction.
The Explanation: The numbers are different indeed, and both of them are accurate. Quite simply, these passages are talking about two different people. 2 Samuel 23:8 says he was a Tahchemonite by the name of Josheb-basshebeth while 1 Chronicles 11:11 is talking about a Hachmonite by the name of Jashobeam. There is no contradiction here.