Though in theory a person may be Pelagian, in the practice of the Christian life, above all in prayer, every Christian is an Augustinian. Self-glorying is excluded, and God alone is given the honor. Even foreknowledge by definition, includes predestination. Either God knows the elect with certainty or not at all. If He does, foreknowledge is redundant. If not, even foreknowledge has to go. The doctrine of predestination, therefore, is a dogma of the entire Christian church.
Reformed Dogmatics by Herman Bavinck, Volume Two: God and Creation, p. 339