This Bible contradiction is from the Skeptic's Annotated Bible.

Verses

300

1 Chronicles 11:11 View context

And this [is] the number of the mighty men whom David had; Jashobeam, an Hachmonite, the chief of the captains: he lifted up his spear against three hundred slain [by him] at one time.

800

2 Samuel 23:8 View context

These [be] the names of the mighty men whom David had: The Tachmonite that sat in the seat, chief among the captains; the same [was] Adino the Eznite: [he lift up his spear] against eight hundred, whom he slew at one time.