Hi Dodo...
Isaiah 55:8-9 is talking about the old heart before Christ, the natural man... after Christ all as changed and HE shows us everything for we have the mind of Christ.... read carefully what Paul says about this:
Howbeit we speak wisdom among them that are perfect: yet not the wisdom of this world, nor of the princes of this world, that come to nought:
But we speak the wisdom of God in a mystery, {even} the hidden {wisdom}, which God ordained before the world unto our glory:
Which none of the princes of this world knew: for had they known {it}, they would not have crucified the Lord of glory.
But as it is written, Eye hath not seen, nor ear heard, neither have entered into the heart of man, the things which God hath prepared for them that love him.
But God hath revealed {them} unto us by his Spirit: for the Spirit searcheth all things, yea, the deep things of God.
For what man knoweth the things of a man, save the spirit of man which is in him? even so the things of God knoweth no man, but the Spirit of God.
Now we have received, not the spirit of the world, but the spirit which is of God; that we might know the things that are freely given to us of God.
Which things also we speak, not in the words which man's wisdom teacheth, but which the Holy Ghost teacheth; comparing spiritual things with spiritual.
But the natural man receiveth not the things of the Spirit of God: for they are foolishness unto him: neither can he know {them}, because they are spiritually discerned.
But he that is spiritual judgeth all things, yet he himself is judged of no man. {judgeth: or, discerneth} {judged: or, discerned}
For who hath known the mind of the Lord, that he may instruct him? But we have the mind of Christ. {may: Gr. shall}
1 Co2:6-16.
God is no longer a mystery for their sons because it reveals them HIS own heart... and this new heart is the new covenant...
Therefore say unto the house of Israel, Thus saith the Lord GOD; I do not {this} for your sakes, O house of Israel, but for mine holy name's sake, which ye have profaned among the heathen, whither ye went.
And I will sanctify my great name, which was profaned among the heathen, which ye have profaned in the midst of them; and the heathen shall know that I {am} the LORD, saith the Lord GOD, when I shall be sanctified in you before their eyes. {their: or, your}
For I will take you from among the heathen, and gather you out of all countries, and will bring you into your own land.
Then will I sprinkle clean water upon you, and ye shall be clean: from all your filthiness, and from all your idols, will I cleanse you.
A new heart also will I give you, and a new spirit will I put within you: and I will take away the stony heart out of your flesh, and I will give you an heart of flesh.
And I will put my spirit within you, and cause you to walk in my statutes, and ye shall keep my judgments, and do {them}.
And ye shall dwell in the land that I gave to your fathers; and ye shall be my people, and I will be your God.
I will also save you from all your uncleannesses: and I will call for the corn, and will increase it, and lay no famine upon you.
And I will multiply the fruit of the tree, and the increase of the field, that ye shall receive no more reproach of famine among the heathen.
Then shall ye remember your own evil ways, and your doings that {were} not good, and shall lothe yourselves in your own sight for your iniquities and for your abominations.
Ez 36:22-31
GOD makes no sense in the human logic, but HE does for the one who knows HIM... HIS logic is beyond mankind, but not his sons because HE shows them what HE is doing and why.
What don't you understand about no free-will my friend? What's blocking you?
Ask and I'll explain it as good has GOD allows me to.