من لا يحضره الفقيه, volume 1, page 364

Hadith.1044 - Murazim ibn Hakim al-Azdi said: "I was ill for four months and did not perform any voluntary prayers (nawafil) during that time. I mentioned this to Imam Jafar ibn Muhammad Al-Sadiq (as), Imam (as) said: 'There is no obligation upon you for making up those prayers. Indeed, the sick person is not like the healthy one. Whatever Allah (swt) has made overpowering upon him, Allah (swt) is more entitled to excuse him.'"

Translation: Bab Ul Qaim Publications — attributed by Thaqalayn·The Arabic above is the original.

Hadith.1045 - Ali ibn Ja'far asked his brother Imam Musa ibn Jafar Al-Kadhim (as) on whether it is permissible for a man to lean against the wall of the mosque while he is praying, or to place his hand on the wall while standing, without any illness or condition?" He (as) replied: "There is no harm in that." He also asked: "What about a man who is praying the obligatory prayer, and in the first two rak'ahs, he stands up and leans on the side of the mosque to help him rise, without any weakness or condition?" He (as) replied: "There is no harm in that either."

Translation: Bab Ul Qaim Publications — attributed by Thaqalayn·The Arabic above is the original.

Hadith.1046 - Hamad ibn Othman said: I said to Imam Jafar ibn Muhammad Al-Sadiq (as): 'The standing in prayer has become very difficult for me.' He (as) replied: 'When you want to catch the prayer of the one standing, recite while sitting. When there remain two verses of the surah, then stand up and complete the remaining part, and bow and prostrate. That is the prayer of the one standing.'"

Translation: Bab Ul Qaim Publications — attributed by Thaqalayn·The Arabic above is the original.