Sahih Bukhari

The Prophet (ﷺ) said, "Whoever frees a Muslim slave, Allah will save all the parts of his body from the (Hell) Fire as he has freed the body-parts of the slave." Sa`id bin Marjana said that he narrated that Hadith to `Ali bin Al-Husain and he freed his slave for whom `Abdullah bin Ja`far had offered him ten thousand Dirhams or one-thousand Dinars.

I asked the Prophet, "What is the best deed?" He replied, "To believe in Allah and to fight for His Cause." I then asked, "What is the best kind of manumission (of slaves)?" He replied, "The manumission of the most expensive slave and the most beloved by his master." I said, "If I cannot afford to do that?" He said, "Help the weak or do good for a person who cannot work for himself." I said, "If I cannot do that?" He said, "Refrain from harming others for this will be regarded as a charitable deed for your own good."

The Prophet (ﷺ) ordered us to free slaves at the time of solar eclipses.

We were ordered to free slaves at the time of lunar eclipses.

The Prophet (ﷺ) said, "Whoever manumits a slave owned by two masters, should manumit him completely (not partially) if he is rich after having its price evaluated."

Allah's Messenger (ﷺ) said, "Whoever frees his share of a common slave and he has sufficient money to free him completely, should let its price be estimated by a just man and give his partners the price of their shares and manumit the slave; otherwise (i.e. if he has not sufficient money) he manumits the slave partially."