الكافي 1/4/124/23

23. Ali ibn Muhammad has narrated from Muhammad ibn ’Isma‘il ibn Ibrahim ibn Musa ibn Ja‘far ibn Muhammad عليه السلام from Ali ibn ‘Abd al-Ghaffar who has said the following. “When abu Muhammad عليه السلام was imprisoned, the ‘Abbassids, Salih ibn Wasif, Salih ibn Ali and others who were not Shi‘as all came to Salih ibn Wasif asking him to exert more pressure on abu Muhammad عليه السلام .Salih told them, “What should I do? I managed to find two people who were of the harshest manners and appointed them to guard him they both turned into most assiduous worshippers in prayers and fasting. When I asked them about their behaviors they replied, “What would you say about a man who fasts every day, worships the whole night and does not speak or busy himself with anything? When we look at him a feeling of trembling and shivering over takes us and we lose control over our own selves.” When they heard this they returned in despair.”