“Words with the δουλ – stem appear a total of 182 times in the NT. Most of these occurrences are of δουλεύω, be a slave, serve (25 occurrences) and δοῦλος, slave, servant (124). They appear most frequently in the Pauline Epistles (47) and the Synoptic Gospels and Acts (71)” (Exegetical Dictionary of the New Testament, 1:349).
Limited to Matthew, Mark and John for the life of Christ (Mt. 6:24; Lk. 15:29; 16:13; Jn. 8:33), the Greek verb “douleuo” meant “slave” or “be subject to obey.” “The word slave refers to above all to a legal status, that of an object of property” (Spicq, 1:381).
Jesus said man cannot “serve” two masters (Mt. 6:24; Lk. 16:13). Paul said it is possible to “serve” sin (Rom. 6:6). It is also possible to “serve” the Lord (Rom. 12:11; 14:18; Col. 3:24). As in the past, some “serve” various lust and pleasures (Tit. 3:3).