How do Reformed people defend God’s sovereignty over Joshua’s call to the Israelites to CHOOSE ye this day whom ye will serve?

John Hendryx answers: Similar to Deut. 29:4-30:16

“But to this day the Lord has not given you a heart to understand or eyes to see or ears to hear.” – Deut 29:4

“And the Lord your God will circumcise your heart and the heart of your offspring, so that you will love the Lord your God with all your heart and with all your soul, that you may live.” Deut 30:6

“See, I have set before you today life and good, death and evil. If you obey the commandments of “the Lord your God that I command you today, by loving the Lord your God, by walking in his ways, and by keeping his commandments and his statutes and his rules, then you shall live…” – Deut. 30:15, 16

When you read these texts together God indeed requires obedience, but he also gives the grace necessary to obey. God Grant’s what he requires.