I think promising kids something is a way for them to always think that they deserve something whenever you send them an errand so it is better not to promise them anything at all.
Promising kids will only make them feel entitled to your property. Truly, a good parent promises his kids because he wants to make them happy but don’t you think a surprise is better than promises.
If you promise your kids anything, they will be expecting it and it won’t even make them happy like giving them a surprise. Surprise makes them more happy and even your kids will pray for you when you surprise them.
Also, it is said that a surprise is better than a promise fulfilled by force. When you promise them, you’ll have no choice than to fulfill that promise whether it is at your own detriment or not. You’ll just have to fulfill it because their minds will be there.
Ecclesiastes 5:4 says; 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.
Most people make promises to God just because they want something and after they get it, they will only fulfill that promise because they have said it to God earlier and not because it comes from the depth of their heart.
That’s just the same as making promises to people or your children.
Also in Ecclesiastes 5:5, the Bible says, Better is it that thou shouldest not vow, than that thou shouldest vow and not pay
So it’s better not to make promises or vow. Just do what you want to do at the right time or the time when it is convenient for you. God doesn’t even want you to make a vow to him and I do not think there is any part of the Bible where Jesus Christ taught us to make vows.
Just make surprises as that is better than promises.