"This is what the LORD says: 'Let not the wise man boast of his wisdom or the strong man boast of his strength or the rich man boast of his riches, but let him who boasts boast about this: that he understands and knows me, that I am the LORD, who exercises kindness, justice and righteousness on earth, for in these I delight,' declares the LORD" (Jeremiah 9:23-24, NIV).
"And now, Israel, what does the LORD your God require of you, but to fear the LORD your God, to walk in all his ways, to love him, to serve the LORD your God with all your heart and with all your soul, and to keep the commandments and statutes of the LORD, which I am commanding you today for your good? Behold, to the LORD your God belong heaven and the heaven of heavens, the earth with all that is in it. Yet the LORD set his heart in love on your fathers and chose their offspring after them, you above all peoples, as you are this day. Circumcise therefore the foreskin of your heart, and be no longer stubborn" (Deut. 10:12-16, ESV).
Again, "Circumcise therefore the foreskin of your heart, and be no longer stubborn."
Of course, we could not "circumcise" our heart literally. But, could we just choose or decide to do it? Could we just exercise our so-called power of the human will and "be no longer stubborn"?
We also read Ezekiel 18:31, “Cast away from you all the transgressions that you have committed, and make yourselves a new heart and a new spirit! Why will you die, O house of Israel?”
Could our so-called “freedom of choice” enable us to “make… a new heart and a new spirit” or “Repent and turn from all your transgressions” (verse 20)?
Could we just love God, or forsake our stubbornness, or repent just by the operation of the human will?
It’s easy to claim that we are able to do it. But consider God’s Word:
"This is the word of the LORD to Zerubbabel: Not by might, nor by power, but by my Spirit, says the LORD of hosts” (Zechariah 4:6).
In Deuteronomy 30:6, we read:
"And the LORD your God will circumcise your heart and the heart of your offspring, so that you will love the LORD your God with all your heart and with all your soul, that you may live."
We also read in Ezekiel 11:19-20, “And I will give them one heart, and a new spirit I will put within them. I will remove the heart of stone from their flesh and give them a heart of flesh, that they may walk in my statutes and keep my rules and obey them. And they shall be my people, and I will be their God.”
And it was emphasized in Ezekiel 36:26-27:
“And I will give you a new heart, and a new spirit I will put within you. And I will remove the heart of stone from your flesh and give you a heart of flesh. And I will put my Spirit within you, and cause you to walk in my statutes and be careful to obey my rules.”
Some claim that that promise is intended only for the physical Israelites. Unknowingly, they promote the “power of the human will," that they could just change their heart!
But even in the New Testament, God’s Word is clear:
“But a Jew is one inwardly, and circumcision is a matter of the heart, by the Spirit, not by the letter. His praise is not from man but from God” (Romans 2:29). Notice: “circumcision is a matter of the heart, by the Spirit” – not by any other means, but “by the Spirit.”
As we also read in Romans 8:8-14:
“Those who are in the flesh cannot please God. You, however, are not in the flesh but in the Spirit, if in fact the Spirit of God dwells in you. Anyone who does not have the Spirit of Christ does not belong to him. But if Christ is in you, although the body is dead because of sin, the Spirit is life because of righteousness…So then, brothers, we are debtors, not to the flesh, to live according to the flesh. For if you live according to the flesh you will die, but if by the Spirit you put to death the deeds of the body, you will live. For all who are led by the Spirit of God are sons of God.”
It’s not by our human will or effort. Whatever “good” intention, decision, or action we have “cannot please God.” We always fall short of His perfect glorious standard.
If ever we love God, or we repent, or we have faith, or are saved, it’s because of His grace. That makes Ephesians 2:8 truly meaningful, “For by grace you have been saved through faith. And this is not your own doing; it is the gift of God.”
Or, in the words of Romans 9:16, “So then it depends not on human will or exertion, but on God, who has mercy.” Because of His mercy, God has caused us through His Spirit to repent, believe in Christ and be saved.