Abdullah bin Abbas (may Allah be pleased with them) narrates that once the Prophet Muhammad (peace and blessings be upon him) saw a man standing in the sun, so he asked (the people) about him. They informed him: This is Abu Isra’il; he has vowed that he will stand in the sun, not sit, not go into the shade, not speak, and will fast. The Prophet (peace and blessings be upon him) said: Tell him to speak, come into the shade, sit down, and complete his fast.