Generous Justice: How God’s Grace Makes Us Just by Tim Keller may be more relevant now than when it was first published in 2010, as our society (both believers and non-believers) is so deeply divided over the very definition of justice. You can read my review of the book here.
Here are 15 more great quotes from the book:

• The most frequently cited Biblical motivation for doing justice is the grace of God in redemption.
• If a person has grasped the meaning of God’s grace in his heart, he will do justice.
• If he (believer) doesn’t care about the poor, it reveals that at best he doesn’t understand the grace he has experienced, and at worst he has not really encountered the saving mercy of God. Grace should make you just.
• If you look down at the poor and stay aloof from their suffering, you have not really understood or experienced God’s grace.
• When Christians who understand the gospel see a poor person, they realize they are looking into a mirror. Their hearts must go out to him or her without an ounce of superiority or indifference.

• When justice for the poor is connected not to guilt but to grace and to the gospel, this “pushes the button” down deep in believers’ souls, and they begin to wake up.
• God does not want us to merely give the poor perfunctory help, but to ponder long and hard about how to improve their entire situation.
• If you are a Christian, and you refrain from committing adultery or using profanity or missing church, but you don’t do the hard work of thinking through how to do justice in every area of life—you are failing to live justly and righteously.
• Racial prejudice is wrong because it is a denial of the very principle that all human beings are equally sinful and saved by only the grace of God.
• Social reform moves beyond the relief of immediate needs and dependency and seeks to change the conditions and social structures that aggravate or cause that dependency.
• Doing justice in poor communities includes direct relief, individual development, community development, racial reconciliation, and social reform.
• Deeds of mercy and justice should be done out of love, not simply as a means to the end of evangelism. And yet there is no better way for Christians to lay a foundation for evangelism than by doing justice.
• Doing justice necessitates a striking a series of balances. It means ministering in both word and deed, through the local church and as individual agents dispersed throughout the world. It means engaging in relief, and development, and reform.
• When believers seek to do justice in the world, they often find it both necessary and desirable to work with others who do not share their faith.
• In Jesus Christ God identified not only with the poor, but also with those who are denied justice.