Some quick arguments in favour of churches using resources for social justice in this world.
1. I care about justice for myself and fight for it ergo I should care about justice for those around me.
2. I spend personal money/resources on things that increase my comfort in this world (you may be surprised to know that I don't give all money away to evangelistic outreachs). As far as I know, no one has ever accused me of doing something wrong by doing that. Why is it wrong, then, for us to spend money and resources to increase other people's comfort?
3. Evangelism is the proclamation of Jesus Christ as Judge of the world. How can I not care about justice?!!
4. The gospel invites people into a community of what? Surely, it's, amongst other things, a group of people who are godly enough to love justice.
5. If I do evangelism without seeking justice then I will incur the same condemnation the prophets proclaimed upon Israel.
6. The church is commanded to do many things - they should never be pitted against one another. We don't say "let's only do 8 out of the 10 commandments as our resources are not great at the moment." You try to obey everything with what you've got.
7. Given the proviso of 6., I still think that our resources are always enough to do God's will. God always supplies what is necessary for His people to do good, love Jesus and proclaim the gospel. If we feel that we don't have enough then we shouldn't give up trying to follow the Lord (!) but rather ask Him for resources!Personal experience in church ministry has confirmed for me that God supplies when we try to obey Him.