God has always tried to demonstrate to humanity that his purpose never changes. He has also left every person the choice whether to follow his purpose or reject it. That is no contradiction. Bible examples show this.
God has a purpose for us. He has unfolded that purpose in such a way that quite evidently it cannot be changed. God has “predestined” us according to his purpose in Christ, and he will not change his mind.
"In Him also we have obtained an inheritance, being predestined according to the purpose of Him who works all things according to the counsel of his will" (Ephesians 1:11 NKJV).
To demonstrate that his purpose cannot change, God made certain promises in which it is impossible for him to lie. Furthermore, God added his own oath, swearing by himself because he had no person greater to swear by.
Our Father has therefore assured us, by two things that cannot change —his promise and his oath. He has assured us that his purpose stands.
There is nothing in this universe more precious and wonderful than this assurance of hope, the anchor of our souls (Hebrews 6:13-20).
There are people who teach that because God’s purpose is unchangeable, each person’s destiny is unchangeable. There is no freedom of will. This has been debated for centuries and the argument has not abated to this day.
Whatever people may say, God’s word is clear in affirming both things: God’s unchangeable purpose and humanity’s freedom of choice to accept or reject that purpose.
Any two points revealed in God’s word must be consistent with each other. There is no inconsistency between God’s unchangeable purpose and humanity’s freedom of choice. Human philosophy may deny this, but God affirms it in his word.
The clearest confirmation is in Bible examples, three of which I present below...
God’s purpose and will was made perfectly clear to Adam and Eve. Notice how Eve was able to explain to the serpent, in no uncertain terms, exactly what God purposed for her and her husband.
"From the fruit of the trees of the garden we may eat, except for the fruit of the tree which is in the middle of the garden. God has said we must not eat of it lest we die."
That was the unchangeable purpose and will of God. Yet Eve and her husband both chose to eat and consequently to die. They exercised their will in disobedience to God’s will and counsel.
In God’s amazing grace and wisdom, he had provided a way to save Adam and Eve (and all who came after them). But even his scheme of redemption was a matter for their own personal choice and will.
So in our first example we see human will being exercised in rejection of God’s unchangeable purpose. When Adam and Eve did what God forbade, did God change his purpose? No. Adam and Eve could disobey God’s will and purpose for them. But they couldn't change it, and it still applied to them as much as ever.
It was God s clear purpose that human beings should have no other gods. They should worship only him. This was the unchangeable counsel and purpose of God, and he never changed his mind, not for a moment.
Yet people commonly chose to worship gods of their own invention. So Joshua called upon the people to "Choose for yourselves today whom you will serve".
The people made their choice, and declared they would not serve other gods. Then Joshua said, "You are witnesses against yourselves, that you yourselves have chosen the LORD to serve him". Joshua did not tell these people they had no free will. Quite the opposite. He told them that they had exercised personal responsibility and choice.
God’s will for Jerusalem was that he should gather her under his wings. But Jerusalem’s leaders chose otherwise and stoned the prophets God sent. They rejected God in both Old and New Testament times.
Jesus said to the religious leaders, "O Jerusalem, Jerusalem, the one who kills the prophets and stones those who are sent to her! How often I wanted to gather your children together, as a hen gathers her chicks under her wings —but you were not willing".
Speaking of the prophet John, Luke shows how people exercised their own wills to choose for or against God. "When all the people heard Jesus speak of John, even the tax collectors justified God, having been baptised with the baptism of John. The Pharisees and lawyers however rejected the will of God for themselves, not having been baptised by John." (Luke 7:29-30).
Notice carefully the phrases, "you were not willing" and "they rejected the will of God for themselves". The religious leaders were exercising their free will to reject God’s will for them.
Clearly we cannot say God’s will and purpose for some people is that they reject his will and purpose for them. That is contradictory and doesn't make sense. So we must allow that people reject God’s will and purpose of their own free will. That's what the above examples show.
These three of many examples in the Bible make it clear that God’s purpose doesn't change even though people choose to reject it. God’s will still applies and his purpose still stands. People can reject and disobey God’s counsel, but they cannot escape the consequences.
So choose you this day whom you will serve!