Cross reference
Deuteronomy 15:18
18 Let it not seem hard to you that you have to send him away free; for he has been working for you for six years, which is twice the regular time for a servant: and the blessing of the Lord your God will be on you in everything you do.
Isaiah 16:14
14 But now the Lord has said, In three years, the years of a servant working for payment, the glory of Moab, all that great people, will be turned to shame, and the rest of Moab will be very small and without honour.
Isaiah 21:16
16 For so has the Lord said to me, In a year, by the years of a servant working for payment, all the glory of Kedar will come to an end:
Luke 17:7-8
7 But which of you, having a servant who is ploughing or keeping sheep, will say to him, when he comes in from the field, Come now and be seated and have a meal,
8 Will he not say, Get a meal for me, and make yourself ready and see to my needs till I have had my food and drink; and after that you may have yours?