Where is "`At the end of seven years thou dost make a release," found in the Bible?

This verse is found in Deuteronomy, chapter 15, verse 1 of the Young's Literal Translation (YLT) Bible translation.

Deuteronomy 15:1 (YLT) - Bible Verse

`At the end of seven years thou dost make a release,

And Moses said, I will turn aside now, and see this great sight, why the bush is not burnt.