If you are ungrateful, Allah is rich beyond need of any of you and He is not pleased with ingratitude in His servants. But if you are grateful, He is pleased with you for that. No burden-bearer can bear another's burden. Then you will return to your Lord and He will inform you of what you did. He knows what the heart contains. (Qur'an, 39:7)
Why should Allah punish you if you are thankful and believe? Allah is All-Thankful, All-Knowing. (Qur'an, 4:147)
"And when your Lord announced: "If you are grateful, I will certainly give you increase, but if you are ungrateful, My punishment is severe." (Qur'an, 14:7)