By the sovereign will of God, man has free will. God permits man's volition to function in disobedience to His will. God desires that all men be saved. But all men are not saved.
There are 3 types of Divine will. All of which can be found in the book of Numbers chapters 22 and 23 with regard to Balaam as an example.
1) The Directive Will of God:
Num 22:12 And God said to Balaam, ''Do not go with them; you shall not curse the people; for they are blessed.'' 13) So Balaam arose in the morning and said to Balak's leaders, ''Go back to your land, for the LORD has refused to let me go with you.''
It was God's will that Balaam was to refuse to go with the messengers from Balak. '' You will not go. You will not curse.'' Balaam was prohibited from going with the messengers back to their land to curse the Israelites.
2) The Permissive Will of God:
Num 22:20 And God came to Balaam at night and said to him, ''If the men have come to call you, rise up and go with them, but only the word which I speak to you shall you do.
Balak had a second time sent messengers to Balaam asking him to come and curse the Israelites. And Balamm wanted to do so. He wanted the fee that had been promised to him for cursing the Israelites.Therefore, God permitted Balaam to go. Balaam wanted to go contrary to God's directive will. God does not coerce human volition. He disciplines for disobedience, but he does not force obedience. On the way to the land of Moab, the angel of the LORD stood in front of the donkey that Balaam was riding, and blocked his way. 'The angel of the LORD' is a theophany, a pre-incarnation appearance of Jesus Christ. Here is what the angel of the Lord said to Balaam. Num. 22:32 And the angel of the Lord said to him, ''Why have you struck your donkey these three times? Behold, I have come out as an adversary, because your way was contrary to me. 33) But the donkey saw me and turned aside from me these three times. If she had not turned aside from me, I would surely have killed you just now, and let her live.'' 34) And Balaam said to the angel of the LORD, ''I have sinned, for I did not know that you were standing in the way against me. Now then, if it is displeasing to you, I will turn back.'' 35) But the angel of the LORD said to Balaam, ''Go with the men, but you shall speak only the word which I shal tell you.'' So Balaam went along with the leader of Balak.
God did not violate Balaam's free will, but He did discipline him for disobedience. That God allowed Balaam to go indicates God's recognition of human volition. In grace, God tried to deter Balaam so that He would not have to discipline him. But Balaam wanted to go and God stood aside and allowed Balaam to go.
C.I Scofield wrote...
(22:5) Balaam was a typical hireling prophet, seeking only to make a market of his gift. This is the way of Balaam (2 Pet. 2:15) and characterizes false teachers. The error of Balaam ( Jude 11) was that he could see only the natural morality. A holy God, he reasoned, must curse such a people as Israel. Like all false teachers he was ignorant of the higher morality of vicarious atonement, by which God could be just and yet the justifier of believing sinners (Rom. 3:26).
The doctrine of Balaam (Rev.2:14) refers to his teaching Balak to corrupt the people whom he could not curse (cp.Num.31:16 with Num. 25:1-3 and Jas.4:4). Spiritually, Balaamism in teaching never rises above natural reasonings; in practice, it is easy world-conformity. See Rev.2:14, note.
(22:22) In v. 12 the directive will of the LORD was made known to Balaam; in v.20, the LORD's permissive will. The prophet was now free to go but knew the true mind of the LORD about it. The matter was wholly one between the LORD and His servant. The permission of v. 20 really constituted a testing of Balaam. He chose the path of self-will and self-advantage, and the LORD could not but gravely disaprove. The whole scene (vv.22-35) prepared Balaam for what was to follow.
(New Scofield Reference Edition, footnote for Numbers 22:5, 22:22, pages 197,198).
3) The Overruling Will of God.
Numbers 23:5,11,12,25,26 Then the LORD put a word in Balaam's mouth and said, ''Return to Balak, and you shall speak thus.'' 11)Then Balak said to Balaam, ''What have you done to me? I took you to curse my enemies, but behold, you have actually blessed them!'' 12) And he (Balaam) answered and said, ''Must I not be careful to speak what the LORD puts in my mouth?'' 25) Then Balak said to Balaam, ''Do not curse them at all nor bless them at all!'' 26) But Balaam answered and said to Balak, ''Did I not tell you, 'Whatever the LORD speaks, that I must do'?''
God did not allow Balaam to curse the Israelites because the discipline and judgment of Israel is always God's sovereign exclusive right. And had Balaam cursed the Jews, it would have amounted to anti-Semitism. In keeping with His promise in Genesis 12:2, He used His overruling will, His divine sovereignty to guard and protect His people from Satans attempt to curse them.
God's Directive will is the exercise of His sovereignty, which in the case of Balaam, did not permit him to curse Israel. God's Permissive will allows the negative volition of man as in the case with Balaam. God's Overruling will frustrates Satan's will. It was Satan who wanted to curs Israel, but God did not allow it to happen.
Man's ability to reject God's offer of salvation falls under God's Permissive will. God desires that all men be saved. But He does not overrule man's negitive volition toward the Gospel just as He did not overrule Satan's negative volition when he rebelled against God.
John 3:36 'He who believes in the Son has eternal life; but he who does not obey (God's Permissive will allows man to disobey) the Son shall not see life, but the wrath of God abides on him.'' ( God's punishes the negative volition of man. Rejecting God's offer of salvation through faith in Christ results in eternal destruction in the lake of fire. Not in the sense of cessation of existence, but destruction in the sense of eternal ruin and uselessness in torment. Perish-Apollumi-Strongs Number G622.)
It is God's will that all believers be filled with the Holy Spirit. Eph. 5:18. But not all believers are.
It is God's will that believers give thanks in everything. 1 Thess. 5:18. But not all believers give thanks in everything.
It is God's will that believers trust Him. Prov. 3:5. But not all believers trust Him.
It is God's will that men obey authority and do what is right. 1 Peter 2:13-15. But not all men obey authority or do what is right.
It is God's desire that all men be saved. 1 Tim. 2:4 But not all men are saved. Only those members of the human race who place their trust in Christ for salvation are saved. John 6:40 For this is the will of the Father, that everyone who beholds the Son and believes in Him, may have eternal life; and I Myself will raise him up in the last day'' Not all men believe in Christ. John 8:48 ''I said therefore to you, that you shall die in your sins; for unless you believe that I am, you shall die in your sins.''
See the following links...
Lesson 7 - The Will of God Part 2
D.S. - Devine Guidance
(http://www.gracebiblechurchbaytown.org/doctrine/devine.guidance.htm - broken link)
By the sovereign decree of God, man has free will. And God allows man to reject His free gift of salvation.