Orthopraxy is "right practice" — the doing of what God commands, not merely the knowing of what God has revealed. It is the necessary partner of orthodoxy. James made the point unforgettable: "But be doers of the word, and not hearers only, deceiving yourselves... If anyone thinks he is religious, and does not bridle his tongue but deceives his own heart, this one's religion is useless" (James 1:22-26). And later: "Faith without works is dead" (James 2:17). Orthodoxy without orthopraxy is dead religion — the hypocritical Christianity that Jesus most frequently denounced. Orthopraxy without orthodoxy is blind activism — well-meaning effort disconnected from truth, which is usually just the fashions of the age baptized with Christian words. The Christian life requires both: right belief and right action. You cannot please God with correct theology if your life contradicts it; you cannot please God with good deeds if they flow from false beliefs. "Therefore, whoever hears these sayings of Mine, and does them, I will liken him to a wise man who built his house on the rock" (Matthew 7:24).
James 1:22 — "But be doers of the word, and not hearers only, deceiving yourselves."
James 2:17 — "Thus also faith by itself, if it does not have works, is dead."
Matthew 7:24 — "Therefore, whoever hears these sayings of Mine, and does them, I will liken him to a wise man who built his house on the rock."
1 John 3:18 — "My little children, let us not love in word or in tongue, but in deed and in truth."