Question:What does God do if you make a deal with Him and don't keep it? What does He do to you?
God is not like your best friend of whom you can ask a favor and then promise to something for him in return. Imagine going up to the leader of a country and saying, "Hey, I'm short of cash this month, but if you'll help me out, I'll do you a favor in return -- maybe even vote for you in the next election!" You should find the idea absurd. What could a common citizen offer a great leader in exchange for a favor.
God is the Creator of this universe. Everything in it, including you and I, already belongs to Him. "Thus says the LORD, your Redeemer, And He who formed you from the womb: "I am the LORD, who makes all things, Who stretches out the heavens all alone, Who spreads abroad the earth by Myself; Who frustrates the signs of the babblers, And drives diviners mad; Who turns wise men backward, And makes their knowledge foolishness; Who confirms the word of His servant, And performs the counsel of His messengers; ..."" (Isaiah 44:24-26). What could you offer God, that He does not already have? What could you offer God that He could not create? "All things were made through Him, and without Him nothing was made that was made" (John 1:3). God stated, "Everything under heaven is Mine" (Job 41:11). Now, doesn't it seem a bit foolish to be trying to make deals with God?
However, God has offered us deals or promises. For example, "And this is the promise that He has promised us--eternal life" (I John 2:25). Unlike your promises, God always keeps His word. "God is not a man, that He should lie, nor a son of man, that He should repent. Has He said, and will He not do? Or has He spoken, and will He not make it good?" (Numbers 23:19). Yet those promises are not open ended. God asks us to do things; often small things that are in no way measurable to the things He has promised us, but things which measure our commitment to Him. For example, Peter states that the gift of the Holy Spirit is received after some conditions are meet. "Then Peter said to them, "Repent, and let every one of you be baptized in the name of Jesus Christ for the remission of sins; and you shall receive the gift of the Holy Spirit"" (Acts 2:38). Repentance and being baptized are conditions God has placed on receiving the gift of the Holy Spirit. Neither of these things earn the gift, but without doing these things God will not give the gift.
Christians are expected to be like God in that God expects us to be men of our words. God does not lie, and neither should we. "Do not lie to one another, since you have put off the old man with his deeds, and have put on the new man who is renewed in knowledge according to the image of Him who created him" (Colossians 3:9-10). Under the Old Testament, God was very serious about people who made promises to Him or in His name. "Do not be rash with your mouth, and let not your heart utter anything hastily before God. For God is in heaven, and you on earth; therefore let your words be few. ... When you make a vow to God, do not delay to pay it; for He has no pleasure in fools. Pay what you have vowed - better not to vow than to vow and not pay" (Ecclesiastes 5:2, 4-5).
What will God do when we don't keep our word? He will hold us accountable. "But I say to you that for every idle word men may speak, they will give account of it in the day of judgment. For by your words you will be justified, and by your words you will be condemned" (Matthew 12:36-37). When we don't keep our word, it means that we have lied. When we don't keep our word to God, we have lied to our Lord and Master. "But the cowardly, unbelieving, abominable, murderers, sexually immoral, sorcerers, idolaters, and all liars shall have their part in the lake which burns with fire and brimstone, which is the second death" (Revelation 21:8). God justly punishes those who make false promises.