Sa'id bin Umayr, whose maternal grandfather was Sayyiduna al-Bara' bin Azib (may Allah be pleased with him), narrates that the Prophet (peace and blessings be upon him) was asked: "Which of a man's earnings is the purest?" He (peace and blessings be upon him) said: "A man's work with his own hand, and every lawful sale."
This is the preserved version, as mursal.
(b) Sa'id narrates from his paternal uncle that the Messenger of Allah (peace and blessings be upon him) was asked: "Which earning is the best?" He said: "A pure earning."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 10398