Albert Barnes Commentary Joshua 24:15

"And if it seem evil unto you to serve Jehovah, choose you this day whom ye will serve; whether the gods which your fathers served that were beyond the River, or the gods of the Amorites, in whose land ye dwell: but as for me and my house, we will serve Jehovah." — Joshua 24:15 (ASV)

Choose - Service of God in sincerity and truth can only result from a free and willing allegiance of the heart. This accordingly is what Joshua invites, as Moses had done before him (Deuteronomy 30:15 and following).