“There is no Muhrim (pilgrim in Ihram) who exposes himself to the sun all day for the sake of Allah, reciting the Talbiyah until the sun goes down, but his sins will disappear and he will go back like on the day his mother bore him.”  

قَالَ رَسُولُ اللَّهِ ﷺ مَا مِنْ مُحْرِمٍ يَضْحَى لِلَّهِ يَوْمَهُ يُلَبِّي حَتَّى تَغِيبَ الشَّمْسُ إِلاَّ غَابَتْ بِذُنُوبِهِ فَعَادَ كَمَا وَلَدَتْهُ أُمُّهُ