"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. Better is it that thou shouldest not vow than that thou shouldest vow and not pay." (Ecclesiastes 5:4-5, emphasis mine)
Defer
It'd be interesting to see how many vows me make on a day-to-day basis that we leave unattended before God. Each thing we purpose to perform, far from being an act of "selfwill" in a negative sense, is something God looks upon in anticipation of the same--performed in love toward Him. And it's one thing to consciously, and in prayer, tell God you're gonna do something for Him. To where it's written on His legal pad (a different shade of yellow than to which we have access on this earth) and then expected to be done just so. But it's quite another to be living under His grace and suffer from a serious case of indecision as to the what, why and how of our daily actions. And everyone is living under His Grace in some way, shape and form:
"For the grace of God that bringeth salvation hath appeared to all men, Teaching us that, denying ungodliness and worldy lusts, we should live soberly, righteously, and godly in this present world." (Titus 2:11)
When I imagine spiritual locales and events, I tend to see a lot in the shape of a courtroom. I had a dream once where I observed one demonic entity cross-examining another, lower in rank. Evidently, the minor one had failed and was stating his case albeit making a fool of himself (kinda scary). It was a dream, I didn't make it up. But with a lot of our mental juggling, I wonder (assuming you believe in Heaven and Hell and the entities that make up either side) about the forces that exert themselves upon our decisions. Because our decisions and actions have consequence. In this world and the next.
"And I will give thee the keys of the kingdom of Heaven: and whatsoever thou shalt bind on earth shall be bound in Heaven: and whatsoever thou shalt loose on earth shall be loosed in Heaven." (Matthew 16:19)
Demur
In legal parlance, a demurrer is simply a written counter to the charges brought against the defendant. I find it helpful to have these legal terms to frame what God's word says regarding our walking in the rules God has laid out for us under Him.
"Whatsoever thy hand findeth to do, do it with thy might..." (Ecclesiastes 9:10a)
So long as it's not sin, have at it. I had a very hard time, growing up, with a sort-of spiritually-tinged OCD. It was a horrible habit of pseudo-superstition that is shattered and exploded with personal knowledge of Jesus as savior and friend. To where the cascade of something akin to "the law" held sway out of fear. I was horribly afraid of not doing things just right so as to incur some sort of judgment that manifested itself as a mild depression or worse. But Jesus does away with all that with a look. And He is always looking at us. "He ever liveth to make intercession for [us]." (Hebrews 7:25b)
So I suppose God was the judge in that case (the dream). I think about the vantage point from which I observed the drama. And I felt like a little kid (I must've been dreaming in my late teens/early twenties) amidst the seriousness of the proceedings. This kind of standing is given to us by Jesus to where we demur at the outset, any strict rule-keeping the enemy would seek to inundate us with as we go about our merry way--in love.