It is really difficult to find information about Christoph Blumhardt yet a read of the collection of essays Action In Waiting is really rewarding.
His writings can be found as free dowloadable e books on the Plough Publishing web site, see the link Christoph Blumhardt.
He had a substantial influence on Karl Barth who observed that Blumhardt ... can do something which most of us cannot do: represent God’s cause in the world yet not wage war on the world, love the world and yet be completely faithful to God, suffer with the world and speak a frank word about its need while simultaneously going beyond this to speak the redemptive word about the help it awaits.
Blumhardt, particularly in his understanding and account of the kingdom of God does not easily fit into our narrow theological categories as the following account of his life makes clear:
Christoph Friedrich Blumhardt (1842-1919) was born at Möttlingen in 1842,. As his father had done before him, he took university training pointing toward a Reformed pastorate. However, he became disillusioned with the church and theology and so decided simply to return home to Bad Boll and act as a helper working with his father at the retreat and healing centre there.
In time, the younger Blumhardt became quite renowned as a mass evangelist and faith healer. But after a very successful “crusade” in Berlin in 1888, he drastically cut back both activities, saying,
"I do not want to suggest that it is of little importance for God to heal the sick; actually, it now is happening more and more often—although very much in quiet. However, things should not be promoted as though God’s kingdom consists in the healing of sick people. To be cleansed is more important than to be healed. It is more important to have a heart for God’s cause, not to be chained to the world but be able to move for the kingdom of God."
Blumhardt’s interest gradually took what could be called “a turn to the world,” namely, a focus upon the great socioeconomic issues of the day. Under the impetus of this concern Blumhardt chose, in a public and conspicuous way, to cast his lot with Democratic Socialism, the much maligned workers’ movement that then was fighting tooth and nail for the right of the working class. Although it brought upon his head the wrath of both the civil and ecclesiastical establishments, he addressed protest rallies, ran for office on the party slate, and was elected to a six-year term in the Württemberg legislature. He was asked to resign his ministerial status in the church. Blumhardt began as a very active and energetic legislator, but as time passed he greatly curtailed this activity and bluntly declined to stand for a second term of office. Clearly, the pattern was of a piece with his earlier retreat from mass evangelism and faith healing.
Blumhardt’s disillusionment with Democratic Socialism—i.e., with the party politics, not with the movement’s purposes and ideals—and the even greater disillusionment which came toward the close of his life with the dark years of World War I—these brought him to a final position expressed in the dialectical motto: Wait and Hasten. His understanding was that the call of the Christian is still for him to give himself completely to the cause of the kingdom. To do everything in his power to help the world toward that goal. Yet, at the same time, a Christian must remain calm and patient, unperturbed even if his efforts show no signs of success, willing to wait for the Lord to bring the kingdom at his own pace and in his own way. And, according to Blumhardt, far from being inactivity, this sort of waiting is itself a very strong and creative action in the very hastening of the kingdom.
Excerpted from the introduction to Thy Kingdom Come: A Blumhardt Reader by Vernard Eller