Any scripture that gives us a command or calls us to obedience is an affirmation of free will because it affirms that we have a choice and an ability to disobey.
Sirach 15:15-16 If you will, you can keep the commandments, and to act faithfully is a matter of your own choice. He has placed before you fire and water: stretch out your hand for whichever you wish.
Luke 10:16 He that hears you hears me; and he that rejects you rejects me; and he that rejects me rejects him that sent me.
Jeremiah 21:8-9 And unto this people thou shalt say, Thus saith the Lord; Behold, I set before you the way of life, and the way of death. He that abideth in this city shall die by the sword, and by the famine, and by the pestilence: but he that goeth out, and falleth to the Chaldeans that besiege you, he shall live, and his life shall be unto him for a prey.
We make choices every day -
Do I wear the green shirt or the blue shirt today? Should I buy a Chevy or a Ford...
In this I will grant that we have a free will. We can choose at any given circumstance whether to do one thing or another, even to the point of whether to sin or not. We do have those choices. Where we do NOT have a choice is to honor, glorify, rejoice in, or seek God. There is no choice in that. We (before regeneration) are sinners dead to God. We cannot choose to become alive in God. Not on our own action, decision, desire or in any other way. God chooses us. Then he paves the way for us to believe in him.