Abdullah bin Abbas (may Allah be pleased with them both) narrates that the Prophet Muhammad (peace be upon him) passed by a man named Abu Isra’il, who was standing in the sun. The Prophet (peace be upon him) inquired:“What is the matter with him?”They informed him that he had vowed not to speak, not to seek shade, not to sit down, and to fast. The Prophet (peace be upon him) said:“Tell him to speak, to come into the shade, to sit down, and to continue his fast.”(The narrator says:) The Prophet (peace be upon him) did not instruct him to offer any expiation.