1401. doulos -- a slave
... under Christ's authority as His devoted followers. Word Origin of uncertain derivation
Definition a slave NASB Word Usage bond-servant (11), bond-servants (12 ...
/greek/1401.htm - 7kPsalm 40:6
Sacrifice and offering you did not desire; my ears have you opened: burnt offering and sin offering have you not required.
Torrey's Topical Textbook—AKJV

Hebrews 10:5
Why when he comes into the world, he said, Sacrifice and offering you would not, but a body have you prepared me:
Torrey's Topical Textbook—AKJV

Philippians 2:7,8
But made himself of no reputation, and took on him the form of a servant, and was made in the likeness of men:
Torrey's Topical Textbook—AKJV