Hadith 4725
وَعَنْ أَبِي هُرَيْرَةَ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: «إِذَا كَانَ أَحَدُكُمْ فِي الْفَيْء فقلص الظِّلُّ فَصَارَ بَعْضُهُ فِي الشَّمْسِ وَبَعْضُهُ فِي الظل فَليقمْ» . رَوَاهُ أَبُو دَاوُد
It is narrated from Abu Hurairah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "When any one of you is in the shade, then the (shade) moves away from him and part of his body is in the sun and part in the shade, then he should get up (from there)." Hasan, narrated by Abu Dawood.