وَعَنْ أَنَسٍ
قَالَ: كَانَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: لَا يَعُودُ مَرِيضًا إِلَّا بَعْدَ ثَلَاثٍ
Anas said the Prophet (sallallahu alayhi wa sallam) was not accustomed to visit an invalid till he had been ill for three days. Ibn Majah and Baihaqi, in Shuab al- iman, transmitted it.