These are the first three meanings of slave from the Free Online Dictionary:
1. One bound in servitude as the property of a person or household. 2. One who is abjectly subservient to a specified person or influence. . . 3. One who works extremely hard.
Exodus 21:2 When you buy a Hebrew slave, he shall serve six years, and in the seventh he shall go out free, for nothing. 3 If he comes in single, he shall go out single; if he comes in married, then his wife shall go out with him. 4 If his master gives him a wife and she bears him sons or daughters, the wife and her children shall be her master's, and he shall go out alone. 5 But if the slave plainly says, ‘I love my master, my wife, and my children; I will not go out free,’ 6 then his master shall bring him to God, and he shall bring him to the door or the doorpost. And his master shall bore his ear through with an awl, and he shall be his slave forever. (ESV)
Philippians 2:3 Do nothing from rivalry or conceit, but in humility count others more significant than yourselves. 4 Let each of you look not only to his own interests, but also to the interests of others. 5 Have this mind among yourselves, which is yours in Christ Jesus,  6 who, though he was in the form of God, did not count equality with God a thing to be grasped, 7 but made himself nothing, taking the form of a servant, being born in the likeness of men. 8 And being found in human form, he humbled himself by becoming obedient to the point of death, even death on a cross. 9 Therefore God has highly exalted him and bestowed on him the name that is above every name, 10 so that at the name of Jesus every knee should bow, in heaven and on earth and under the earth, 11 and every tongue confess that Jesus Christ is Lord, to the glory of God the Father. (ESV)
 1:1 Or slaves; Greek bondservants  2:5 Or which was also in Christ Jesus (ESV)
Ephesians 5:16 making the best use of the time, because the days are evil. 17 Therefore do not be foolish, but understand what the will of the Lord is. 18 And do not get drunk with wine, for that is debauchery, but be filled with the Spirit, 19 addressing one another in psalms and hymns and spiritual songs, singing and making melody to the Lord with all your heart, 20 giving thanks always and for everything to God the Father in the name of our Lord Jesus Christ, 21 submitting to one another out of reverence for Christ. (ESV)
There is a second part, with a few quotations from non-Biblical literature.Thanks for reading.