If God told Israel to choose then it follows that they had the power to choose. By definition our "will" is our ability to make choices. But I have another scripture that proves the same point. In the following scriptures I have typed the choices that God wants Israel to make in bold.
“Wash you, make you clean;
put away the evil of your doings from before mine eyes;
cease to do evil;
Learn to do well;
seek judgment,
relieve the oppressed,
judge the fatherless,
plead for the widow.
(Isaiah 1:16-17)
God would not command them to do something that was impossible for them to do. In fact God is relying on the fact that they have a will.
In the rest of the passage God appeals to their reason in order to persuade them to make the right choice
Come now, and let us reason together, saith the Lord:
though your sins be as scarlet, they shall be as white as snow; though they be red like crimson, they shall be as wool.
(Isaiah 1:18)
This shows God's kind intention towards not just SOME but ALL of the people, anyone who would listen, at any rate. God did not want them to harden their hearts and bring them to judgment. If He had wanted to do that He need never have said anything to them.
Next God uses the conditional word IF indicating that they were able to follow or refuse his offer.
If ye be willing and obedient, ye shall eat the good of the
land:
But if ye refuse and rebel, ye shall be devoured with the sword: for the mouth of the
Lord hath spoken it” (Isa. 1:19-20)
Offering someone a motive - reward and punishment - presupposes that their decision can be influenced. The mind reasons, considering both courses of action and then the person decides if their sin is worth it. I do not see anything in here about God determining what they would think or choose.