You are presenting "oath" only as an an intended absolute, presented in self-determinism.
That is what the scriptures says.
Numbers 30:2
If a man vow a vow unto the Lord, or swear an oath to bind his soul with a bond; he shall not break his word,
he shall do according to all that proceedeth out of his mouth.
For some people, it is, no doubt.
It doesn't matter if they do not see it as self detemination. In His words, God says they have to do ALL that proceed out of their mouths because that is their oath and the work of their hands.
To make matters worse, God warns about the consequence for making any oath & even saying it was a mistake on his part to the angel is not going to wash.
Ecclesiastes 5:4 When thou vowest a vow unto God, defer not to pay it; for he hath no pleasure in fools: pay that which thou hast vowed. 5 Better is it that thou shouldest not vow, than that thou shouldest vow and not pay
. 6 Suffer not thy mouth to cause thy flesh to sin; neither say thou before the angel, that it was an error: wherefore should God be angry at thy voice, and destroy the work of thine hands? 7 For in the multitude of dreams and many words there are also divers vanities: but fear thou God.
Some even declare an oath that is meant against God. But that isn't the way it always is.
Can't recall any right now. You have an example?
FWIW, I agree with you in my distaste for the notion that we have our part and God his, as if we can do anything valid apart from him.
The point is under the Old Covenant, man had their chance under the law to make themselves good and to do good to obtain salvation by but failed and so now the New Covenant is God's turn and He said He will do it, and all that is asked of you is to believe Him; not just for salvation as your Saviour, but as your Good Shepherd & Friend to help you to follow Him and all He asks from you is to believe Him.
There are many believers today that resort to their own power under the law to obtain the assurance of salvation by making a commitment to follow Christ and keeping it to gain that assurance of salvation by which is the knowledge of sin and thus defats the purpose for making such a commitment. Some quit, saying it is too hard because that is what a believer's commitment means in the eyes of the religious world because if the man keeps it, it goes to his credit & his glory for keeping it and not to God.
To simply live by faith in Jesus Christ as our Good Shepherd to help us to follow Him seems foolish to the religious people and weak, but He is the power for living the Christian life. That is why many are actually falling away from the faith in Jesus Christ by trying to follow Him by an oath.
2 Timothy 3:1
This know also, that in the last days perilous times shall come. 2 For men shall be lovers of their own selves, covetous,
boasters, proud, blasphemers, disobedient to parents, unthankful, unholy, 3 Without natural affection,
trucebreakers, false accusers, incontinent, fierce, despisers of those that are good, 4 Traitors,
heady, highminded, lovers of pleasures more than lovers of God;
5 Having a form of godliness, but denying the power thereof: from such turn away.
When you recognize that Numbers 30:2 says when a man vows, he is making a man made bondage, and that is not standing fast in the liberty which Christ has set us free, you can ask Jesus for forgiveness and He will set you free from all man made yokes of bondages to rest in Him for following Him just as you rest in Him that you are saved by having believed in Him.
Galatians 5:1Stand fast therefore in the liberty wherewith Christ hath made us free, and be not entangled again with the yoke of bondage..... 5 For we through the Spirit wait for the hope of righteousness by faith.
Otherwise how can you say you had applied Galatians 5:1 to your walk with Christ if you are bonded by an oath?