And I, brethren, when I came to you, did not come with excellence of speech or of wisdom declaring to you the testimony of God. For I determined not to know anything among you except Jesus Christ and Him crucified. I was with you in weakness, in fear, and in much trembling. And my speech and my preaching were not with persuasive words of human wisdom, but in demonstration of the Spirit and of power, that your faith should not be in the wisdom of men but in the power of God. (1 Corinthians 2:1-5)
The Franciscan call says, "Preach the Gospel. When necessary use words." The heart of Christian social action is found in this dictum. God's care for the world should be expressed by His people in acts of mercy and giving. The poor should be cared for, and the oppressed relieved. These actions often speak louder than words, and carry the seed of the Gospel in them.
In comparison evangelical and Pentecostal Christianity sometimes look (and sound) shallow, and pompous next to taking serious social action. Of course Christians should be involved with caring for the impoverished and oppressed of the world, but I wonder if the above words of the Apostle Paul are the connecting dots between social action and Pentecostal faith.
His Gospel, perhaps like that of Francis of Asissi, was not simply spoken, but illustrated. Paul healed the sick and cast out demons. He demonstrated God's power through his prayers and blessings to the impoverished and the oppressed, and he did so in such a way as to emphasize his own weakness. By this he more perfectly illustrated the Gospel - He clearly modeled salvation as an act of God's power moving upon humans despite their incapacity to save themselves.
Healing and deliverance through the miraculous acts of the Spirit of God are still the greatest social action moments of the Biblical narrative. They do not by any means give Christians the right to ignore caring for the poor and oppressed in practical ways, but our knowledge of God's power should cause us to desire the spiritual gifts and move into a wholly new realm of social action.