It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that he said: I grew up an orphan and I emigrated as a poor man, and I was a hired worker for Ibn Affan and the daughter of Ghazwan, in return for the food of my stomach and a turn at riding. I would gather firewood for them when they camped, and chant the camel-song for them when they travelled.
So all praise is for Allah, who made the religion a mainstay and made Abu Hurayrah (may Allah be pleased with him) an imam.
There is nothing in this to show that the Prophet (peace and blessings be upon him) knew of it and let it stand, and it is possible that this was an arrangement between them by way of mutual consent, not by way of a contract.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الإجارة / 11655