Consider two sentences. The first is this: "John Doe is a Presbyterian, but he prays like a Baptist." The second is like unto it: "The key to the Christian life is to believe like a Calvinist and to work like an Arminian."
I have heard those and similar expressions from Reformed folk from time to time, and perhaps you have too. The sentiment behind them is understandablethese comments are designed to challenge Reformed believers from becoming complacent or presumptuous in their spiritual lives. That may be a good idea, but it is very badly executed.
What is dismaying about those statements is the assumption that the Reformed faith offers, by itself, an inadequate approach to sanctification, and it needs to be supplemented from other Christian traditions. I call this the "yin and yang" approach to Reformed spirituality. Two opposing phenomena, Reformed doctrine and evangelical life, if held in precarious balance, actually serve to complement each other, the one supplying the deficiency of the other. So, for example, the light of the Old School needed the heat of the New School. And blended worship allows the reverence of the old and the joyfulness of the new.
My most recent yin and yang sighting was in Christianity Today, last May, where a professor at Calvin College defined himself as a "Reformed Charismatic" or a "Pentecostal Christian." Worshiping at a charismatic church actually made him a better Calvinist, he gushed (unaware, it seems, of the Pelagian accent in the expression, "better Calvinist"). This was because he was freed from Reformed constraints better to experience the sovereignty of God in worship. Don't be scared of this, he urges cautious Calvinists. Jump in because the water is fine.
The folly of this and similar approaches is at least two-fold. First, this is really an insult to Charismatics. Charismatic Christianity is wrong on several scores, but it deserves our respect at least in this sense: its theology and practice are consistent. The Reformed could stand to learn something about the alignment of faith and practice from the charismatic movement.
As popular as this approach may be today, from a Reformed perspective it is ultimately suicidal. This is to be Reformed only on the condition that one's faith contains ideas without consequences. Calvinism is pretty deep stuff, just don't get too carried away with it.
A half-century ago, the Peniel controversy in the Orthodox Presbyterian Church was another manifestation of this alleged tension, when sympathizers of the Peniel Bible Conference in New York accused the OPC of lacking Christian warmth and charity. Would the doctrinally-rich OPC be a stronger church today had it found a way to incorporate the exuberant evangelical piety of Peniel into her corporate culture? The late Charles Dennison did not think so, and here is the lesson he thought Orthodox Presbyterians needed to learn from this episode in their history:
A more profitable approach to the doctrine/life problem is to realize that both sides carry within them what is perceived to stand opposite to them. If both the doctrine and the life side are distinct temperaments in their approaches to Christian faith, they stand holistically, as "systems" complete in themselves. Therefore, the doctrine side has its own perspective on the Christian life; while the life side is not devoid of doctrine but possessed of doctrine essential to its character.
Charlie saw the Reformed faith as J. Gresham Machen did: it was neither experience, nor mere doctrine. Christianity, Machen wrote, was "a way of life founded upon doctrine." Reformed doctrine yields a Reformed way of life, and other traditions produce their own distinctive expressions of Christian piety.
So much then for yin and yang. Since this is an election season, let me close by paraphrasing the great Barry Goldwater. Consistency in the cultivation of Reformed piety is no vice; eclecticism in the pursuit of Presbyterian identity is no virtue.
 Charles G. Dennison, History for a Pilgrim People, ed. by Danny E. Olinger and David K. Thompson (Willow Grove, PA: Committee for the Historian of the OPC, 2002), 144-45.
Ordained Servant, November 2008.