قَالَ رَسُولُ اللٌّهِ (ص): مَا مِنْ وَلَدٍ بَارٍّ نَظَرَ إِلـى أَبَوَيْهِ بِرَحْمَةٍ إِلاَّ كَانَ لَهُ بِكُلِّ نَظْرَةٍ حَجَّةٌ مَبْرُورَةٌ. فَقَالُوا يَا رَسُولَ اللٌّهِ وَ إِنْ نَظَرَ فِي كُلِّ يَوْمٍ مِائَةَ نَظْرَةٍ؟ قَالَ نَعَمْ. أَللٌّهُ أَكْبَرُ وَ أَطْيَبُ.
The Messenger of Allah (peace be upon him and his family) said: “Every righteous child who casts a look of mercy and affection upon his parents shall be granted, for every look of his, rewards equivalent to that of an accepted Hajj.” Those around the Prophet questioned: “O’ Prophet of Allah! Even if he were to look at them a hundred times a day?” The Messenger of Allah (peace be upon him and his family) replied: “Indeed! Allah is the Greatest and Most Kind.”
Biharul Anwar, Volume 74, Page 73