When your servant brings you your food, if you do not ask him to join you, then (at least) give him a bite or two, or a mouthful or two, for he was in charge of preparing it. [Al-Bukhari]

"«إذا أتى أحدَكم خادمُه بطعامِه، فإنْ لم يُجلِسْه معه، فلْيُناوِلْهُ لُقمةً أو لُقْمَتَيْنِ أو أُكْلَة أو أُكْلَتَين، فإنه وَلِيَ عِلاجَه». [صحيح.] - [متفق عليه.]"