The word(s) "serve" appears 100 time(s) in 96 verse(s) in Quran in Muhammad Pickthal translation.

(91) Hast thou not observed those who are hypocrites, (how) they tell their brethren who disbelieve among the People of the Scripture: If ye are driven out, we surely will go out with you, and we will never obey anyone against you, and if ye are attacked we verily will help you. And Allah beareth witness that they verily are liars.

(92) O ye who believe! Observe your duty to Allah. And let every soul look to that which it sendeth on before for the morrow. And observe your duty to Allah. Lo! Allah is Informed of what ye do.

(93) And those who preserve their chastity

(94) (Bidding you): serve Allah and keep your duty unto Him and obey me,

(95) And they are ordered naught else than to serve Allah, keeping religion pure for Him, as men by nature upright, and to establish worship and to pay the poor-due. That is true religion.

(96) Hast thou observed him who belieth religion?