John Calvin 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)

And if it seem evil unto you, and so on. It seems here as if Joshua were paying little regard to what befits an honest and right-hearted leader. If the people had forsaken God and gone after idols, it was his duty to inflict punishment on their impious and abominable revolt.

But now, by giving them the option to serve God or not, just as they choose, he loosens the reins and gives them license to rush audaciously into sin. What follows is still more absurd, when he tells them that they cannot serve the Lord, as if he were actually desirous, by deliberate intent, to impel them to shake off the yoke.

But there is no doubt that his tongue was guided by the inspiration of the Spirit, in stirring up and disclosing their feelings. For when the Lord brings men under his authority, they are usually willing enough to profess zeal for piety, though they instantly fall away from it. Thus they build without a foundation.

This happens because they neither distrust their own weakness as much as they should, nor consider how difficult it is to bind themselves wholly to the Lord. There is need, therefore, of serious examination, lest we be carried away by some reckless impulse and so fail in our very first attempts.

With this design, Joshua, as a test, emancipates the Jews, making them, so to speak, their own masters and free to choose what God they are willing to serve—not with the intention of withdrawing them from the true religion, as they were already too much inclined to do, but to prevent them from making rash promises, which they would soon violate. For the real object of Joshua was, as we shall see, to renew and confirm the covenant which had already been made with God.

Therefore, it is not without reason that he gives them freedom of choice, so that they might not later claim to have been under compulsion, since they bound themselves by their own consent. Meanwhile, to instill in them a sense of shame, he declares that he and his house will persevere in the worship of God.