NASB 1995
"But as for you, speak to the sons of Israel, saying, 'You shall surely observe My sabbaths; for this is a sign between Me and you throughout your generations, that you may know that I am the LORD who sanctifies you.

American Standard Version
Speak thou also unto the children of Israel, saying, Verily ye shall keep my sabbaths: for it is a sign between me and you throughout your generations; that ye may know that I am Jehovah who sanctifieth you.

Berean Study Bible
“Tell the Israelites, ‘Surely you must keep My Sabbaths, for this will be a sign between Me and you for the generations to come, so that you may know that I am the LORD who sanctifies you.

Douay-Rheims Bible
Speak to the children of Israel, and thou shalt say to them: See that thou keep my sabbath: because it is a sign between me and you in your generations: that you may know that I am the Lord, who sanctify you.

English Revised Version
Speak thou also unto the children of Israel, saying, Verily ye shall keep my sabbaths: for it is a sign between me and you throughout your generations; that ye may know that I am the LORD which sanctify you.

King James Bible
Speak thou also unto the children of Israel, saying, Verily my sabbaths ye shall keep: for it is a sign between me and you throughout your generations; that ye may know that I am the LORD that doth sanctify you.

World English Bible
"Speak also to the children of Israel, saying, 'Most certainly you shall keep my Sabbaths: for it is a sign between me and you throughout your generations; that you may know that I am Yahweh who sanctifies you.

Young's Literal Translation
And thou, speak unto the sons of Israel, saying, Only, My sabbaths ye do keep, for it is a sign between Me and you, to your generations, to know that I, Jehovah, am sanctifying you;

Exodus 31:13 Additional Translations ...