Al-Bara’ b. ‘Azib told of a desert Arab who came to the Prophet and said, "Teach me an action which will bring me into paradise.” He replied, "You have asked a large question in few words. Emancipate, a man and set free a slave." He asked if the two were not the same thing, and he replied, "No; emancipating a man is doing it by yourself, and setting free a slave is contributing towards his price. You must also lend for milking a she-camel which has much milk and be well disposed towards a relative who does wrong. If you cannot do that, feed the hungry, give drink to the thirsty, recommend what is reputable and forbid what is disreputable. And if you cannot do that, restrain your tongue from everything but what is good.”
Abu Dharr said he asked the Prophet what action was most excellent, and he replied, "Faith in God and jihad in His path." He then asked which slaves were most excellent 1 and he replied. “Those whose price is highest and who are held in most esteem by their people." He asked what he should do if unable to act accordingly 2 and he replied, "You should assist a workman, or work for one who is unskilled." He asked what he should do if unable to act accordingly and he replied, "Do no harm to others 3 for that is sadaqa you bestow on yourself."
Bukhari and Muslim.
1. i.e. for the purpose of emancipating them.
2. The Arabic is fa-in lam af'al which is somewhat vague. It most probably means he is asking what he should do if unable to emancipate a slave of such quality.
3. This is an accepted meaning of the Arabic tada'u ‘un-nas min ash-sharr. Another possible meaning is to leave people alone because of their evil.
‘Amr b. ‘Abasa reported the Prophet as saying, “If anyone builds a mosque that God may be mentioned in it, a house will be built for him in paradise; if anyone emancipates a Muslim, that will be his ransom from jahannam; if anyone develops a grey hair while in 'God’s path, it will be a light for him on the day of resurrection.”
Abu Huraira reported God's Messenger as saying, "If anyone emancipates a Muslim slave, God will set free from hell a member of the body for every member of his, even his private parts for his."