The Prophet ﷺ forbade sitting between sunlight and shade, saying, "It is the seat of Satan."
أن النبي ﷺ نهى أن يجلس بين الضح والظل وقال: مجلس الشيطان.
Ahmad (15421) narrated it through multiple routes from Hammam, who said, Qatada narrated to us, from Kathir, from Abu Iyad (who is Amr bin Aswad), from a man among the companions of the Prophet ﷺ, and he related it.Its chain is hasan, because Kathir is Ibn Abu Kathir Basri, from whom a group of narrators transmitted, and no one criticized him, while Ajli and Ibn Hibban both affirmed his reliability. His hadith has a firm basis, so it is graded hasan on that account, except that his statement, "the sitting place of Shaytan," has no corroborating narration.Something with a similar meaning has been reported from Abu Hurairah, who said, Abu Qasim ﷺ said, "When one of you is in the sun and the shade shrinks away from him, so that part of him is in the sun and part in the shade, let him get up."Abu Dawud (4821) and Humaydi (1138) both narrated it through the route of Sufyan, who is Ibn Uyayna, from Muhammad bin Munkadir, who said, someone who heard Abu Hurairah say it narrated it to me, and he related it. The teacher of Muhammad bin Munkadir here is unknown.This hadith has been narrated through other chains as well, but they are all defective.