Imam Sadiq AS: Keep God in mind as if you see Him. For even if you do not see Him, but He does see you. If you doubt that God sees you, then you have denied Him, and if you have certainty that He sees you, [but still] sin openly, then you have surely considered Him as the most worthless observer
If the joke is not known to be a joke by the listener, then it is not permissible. And if it is known, then according to the principle of precaution (Ihtiyat Wajib), it is still not permissible. However, one may say something without the intention of conveying news or information, even if it appears to be news on the surface.
