Although the personal relationship of the theologian with God is a reality wider than prayer, since it necessarily involves the entire Christian life, nevertheless prayer is its conscious heart. The fourth-century theologian Father Evagrius of Pontus had a saying, “If you pray, you are a theologian.” The saying has been, perhaps, a little overexposed and not a little misunderstood. The term “theologian” here carries a somewhat specialized meaning. It really means someone who contemplates God as the Trinity. But at least we can echo Evagrius and say, “If you do not pray then you are not a theologian.” It is a necessary (though not a sufficient) condition for becoming a theologian (in the non-Evagrian sense) that one has some kind of prayerful quality to one’s life and thought. How we should understand this is a delicate business. Clearly, it is not the case that if we flop down in a church for half an hour a day we shall emerge from the pew reborn as a latter-day Duns Scotus. But continued exposure to God and a God-centered vision of reality brings a greater quality of intuitive ability when it comes to theological judgment. In other words, if two people who differ on some aspect of theology share a comparable theological culture, but one prays and the other has stopped praying, it is the one who still prays that we should be well advised to follow.
-Aidan Nichols, O.P., The Shape of Catholic Theology, p. 26