"How wonderful it is for one of them that he obeys Allah and fulfills the rights of his master." Meaning the slave. And Ka'b said: "Allah and His Messenger spoke the truth."
Jami` at-Tirmidhi Book 27, Hadith 91
← Previous Hadith "Indeed in Paradise there are chambers, whose outside can be seen from their inside, and their inside can be seen from their outside." A Bedouin stood and said : 'Who are they for, O Messenger of Allah?" He said: "For those who speak well, feed others, fast regularly, and perform salat during the night while the people sleep."

Jami` at-Tirmidhi Book 27, Hadith 90 Next Hadith → "There shall be upon dunes of musk- I think he said: On the Day of Judgment- a slave who fulfills Allah's right and the right of his patron (master), a man who leads a people (in prayer)) and they are pleased with him. And a man who calls for the five prayers during every day and night."

Jami` at-Tirmidhi Book 27, Hadith 92