LXX Deut 5:15

καὶ ήσῃ ὅτι οἰκέτης ἦσθα ἐν γῆ Αἰγύπτῳ, καὶ ἐξήγαγέν σε κύριος ὁ σου ἐκεῖθεν ἐν χειρὶ κραταιᾷ καὶ ἐν βραχίονι ὑψηλῷ· διὰ τοῦτο συνέταξέν σοι κύριος ὁ θεός σου ὥστε φυλάσσεσθαι τὴν ἡμέραν τῶν σαββάτων καὶ ἁγιάζειν αὐτήν.

Remember that you were a slave in the land of Egypt, and that the LORD your God brought you out of there with a mighty hand and an outstretched arm. That is why the LORD your God has commanded you to keep the Sabbath day.