It is narrated from Sayyiduna Husain bin ‘Awf (may Allah be pleased with him) that he came to the Prophet (peace and blessings of Allah be upon him) while he was delivering a sermon. He stood in the sun, so the Prophet (peace and blessings of Allah be upon him) ordered him to move into the shade, and he moved into the shade.
Hadith Referenceالادب المفرد / كتاب / 1174
Hadith Gradingالألبانی:صحيح
Hadith Takhrij«صحيح : أخرجه أبوداؤد ، كتاب الأدب : 4822 - أنظر الصحيحة : 833»
Explanation & Benefits
Shaykh Maulana Usman Muneeb
Benefits and Issues: It is not correct to sit in the sun when there is shade available, especially when the sunlight is harmful. Or, it may be that the Companion was sitting partly in the shade and partly in the sun, and this is what the Prophet sallallahu alayhi wa sallam forbade. (Abu Dawud: 4821) For this reason, he ordered him to sit in the shade. Because such a sitting, in which part is in the shade and part is in the sun, is the sitting place of Shaytan. (Musnad Ahmad: 3/413. Al-Sahihah by Al-Albani, Hadith: 838) By "edge" is meant a place where the sunlight immediately falls.
Source: Fadlullah al-Ahad: Urdu Commentary on al-Adab al-Mufrad, Page: 1174