Have you ever made a promise to someone, and then broke it for some reason? For sure the recipient of that promise got hurt. If ever you've made a promise to God and then failed to fulfill it, God won't like that, too, because that's sin.
Deuteronomy 23:21 says, "When you make a vow to the Lord your God, be prompt in fulfilling whatever you promised Him. For the Lord your God demands that you promptly fulfill all your vows, or you will be guilty of sin."
It is sin
From that verse we understand that breaking promises made to the Lord is simply sin and nothing else. Sin displeases God. It is the one thing that has separated all of mankind from Him. It was for our sin that Christ was crucified on the cross. Shall we break our promises, then, knowing that it is wrong and displeasing to the Lord? We should not.
Some of us rashly made promises unto God. "Lord, if You do [insert demand here] then I will [insert promise to God here]," we say. Friend, doing that is a very unwise thing to do. Think about Jephthah, who made a rash promise to the Lord in Judges 11:30-31.
"And Jephthah made a vow to the Lord. He said, 'If you give me victory over the Ammonites, I will give to the Lord whatever comes out of my house to meet me when I return in triumph. I will sacrifice it as a burnt offering.'"
We read in the following passage that God gave them victory over the enemy. However, Jephthah's victory in the war turned to a sad story for him because of that rashly-made promise: When he returned home, the first person who went out of his house to meet him was his one and only child, his daughter. Jephthah had no choice but to offer her daughter to the Lord because of that vow.
Don't make promises
Friend, it is better to make no promise unto the Lord, but simply do what He says in His Word. Here's what the Lord Jesus said about it, in Matthew 5:33-37.
"You have also heard that our ancestors were told, 'You must not break your vows; you must carry out the vows you make to the Lord.' But I say, do not make any vows! Do not say, 'By heaven!' because heaven is God's throne. And do not say, 'By the earth!' because the earth is his footstool. And do not say, 'By Jerusalem!' for Jerusalem is the city of the great King. Do not even say, 'By my head!' for you can't turn one hair white or black. Just say a simple, 'Yes, I will,' or 'No, I won't.' Anything beyond this is from the evil one."
You see friends, making promises that we cannot fulfill is wrong. Making them, and swearing by yourself or others isn't right either. Jesus Himself said that all of that is "from the evil one." So let's just do our best to make our "yes' be truly "yes" and our "no" truly "no."
