Al-Kāfi - The Book of Prayer

1.Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from ibn abu Nasr from Safwan al-Jammal who has said the following: “Once I performed Salah (prayer) behind abu ’Abd Allah (a.s.), at the time of Zawal (declining of the sun toward the west at noontime) and I asked, saying, ‘I pray to Allah to keep my soul in service for your cause, when is it time for al-‘Asr Salah (prayer)?’ He (the Imam) said, ‘It is when you release your camel.’ I then asked, ‘When it (time of al-‘Asr) is when I am not on a journey?’ He (the Imam) said, ‘It is time for al-‘Asr when it (the shadow of an object) is less than a step or it is two-thirds of a step.’” صحيح - Allamah Baqir al-Majlisi (Mirʾāt al-ʿUqūl fī Sharḥ Akhbār Āl al-Rasūl (5/372))