I'll be preaching on the idea of "service" in about 10 hours. The Bible is full of great passages about this topic. Here are a few of my favorites:

Deut 10:12-13
12 And now, O Israel, what does the LORD your God ask of you but to fear the LORD your God, to walk in all his ways, to love him, to serve the LORD your God with all your heart and with all your soul, 13 and to observe the LORD's commands and decrees that I am giving you today for your own good?
NIV

Josh 24:14-15
14 "Now fear the LORD and serve him with all faithfulness. Throw away the gods your forefathers worshiped beyond the River and in Egypt, and serve the LORD. 15 But if serving the LORD seems undesirable to you, then choose for yourselves this day whom you will serve, whether the gods your forefathers served beyond the River, or the gods of the Amorites, in whose land you are living. But as for me and my household, we will serve the LORD."
NIV

1 Sam 12:20-24
20 "Do not be afraid," Samuel replied. "You have done all this evil; yet do not turn away from the LORD, but serve the LORD with all your heart. 21 Do not turn away after useless idols. They can do you no good, nor can they rescue you, because they are useless. 22 For the sake of his great name the LORD will not reject his people, because the LORD was pleased to make you his own. 23 As for me, far be it from me that I should sin against the LORD by failing to pray for you. And I will teach you the way that is good and right. 24 But be sure to fear the LORD and serve him faithfully
NIV

Matt 6:24
24 "No one can serve two masters. Either he will hate the one and love the other, or he will be devoted to the one and despise the other. You cannot serve both God and Money.
NIV

Matt 20:25-28
25 Jesus called them together and said, "You know that the rulers of the Gentiles lord it over them, and their high officials exercise authority over them. 26 Not so with you. Instead, whoever wants to become great among you must be your servant, 27 and whoever wants to be first must be your slave- 28 just as the Son of Man did not come to be served, but to serve, and to give his life as a ransom for many."
NIV

1 Peter 4:7-11
7 The end of all things is near. Therefore be clear minded and self-controlled so that you can pray. 8 Above all, love each other deeply, because love covers over a multitude of sins. 9 Offer hospitality to one another without grumbling. 10 Each one should use whatever gift he has received to serve others, faithfully administering God's grace in its various forms. 11 If anyone speaks, he should do it as one speaking the very words of God. If anyone serves, he should do it with the strength God provides, so that in all things God may be praised through Jesus Christ. To him be the glory and the power for ever and ever. Amen.
NIV