عِدَّةٌ مِنْ أَصْحَابِنَا عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنْ أَحْمَدَ بْنِ مُحَمَّدِ بْنِ أَبِي نَصْرٍ عَنِ الْحُسَيْنِ بْنِ خَالِدٍ قَالَ قُلْتُ لِأَبِي الْحَسَنِ الرِّضَا ( عليه السلام )
إِنَّ النَّاسَ يَقُولُونَ إِنَّ مَنْ لَمْ يَأْكُلِ اللَّحْمَ ثَلَاثَةَ أَيَّامٍ سَاءَ خُلُقُهُ فَقَالَ كَذَبُوا وَ لَكِنْ مَنْ لَمْ يَأْكُلِ اللَّحْمَ أَرْبَعِينَ يَوْماً تَغَيَّرَ خُلُقُهُ وَ بَدَنُهُ وَ ذَلِكَ لِانْتِقَالِ النُّطْفَةِ فِي مِقْدَارِ أَرْبَعِينَ يَوْماً .
2. A number of our people have narrated from Ahmad ibn Muhammad from Ahmad ibn Muhammad from ibn abu Nasr from al-Husayn ibn Khalid who has said the following: “I once said to abu al-Hassan, al-Rida’ 
, ‘People say that if one does not eat meat for three days his manners change to worse.’ He (the Imam) said,
‘They have spoken lies. However, one who does not eat meat for forty days his manners change and it is because the seed (sperm) transfers (from one stage of development to another) within the duration of forty days.”
