In Scripture, "manifest" describes the divine act of making something hidden visible and known. The greatest manifestation in all of history is the Incarnation: "the life was made manifest, and we have seen it" (1 John 1:2). God manifests himself through Christ, through Scripture, through creation, and through the works of the Spirit in the lives of believers. John 14:21 records Jesus's promise to manifest himself to those who love and obey him. The manifestation of the Spirit is given "for the common good" (1 Corinthians 12:7). Theologically, manifestation is always the disclosure of what was previously concealed — God revealing himself to a world that could not reach him on its own.
MANIFEST, a. Plain, open, clearly visible to the eye or obvious to the understanding; apparent; not obscure or difficult to be seen or understood. MANIFEST, v.t. To make appear; to show plainly; to make visible to the eye or obvious to the understanding; to display; to exhibit. In theology, God manifests his character and will by his works, his word, and especially by the incarnation of his Son.
The New Age movement has seized "manifest" and turned it into a self-help technique: to "manifest" something means to visualize and attract desired outcomes through focused positive thinking (the Law of Attraction). This corrupts the word's fundamental direction: in Scripture, it is God who manifests himself to us — we do not conjure or summon him. The prosperity gospel similarly uses manifestation language to describe calling forth wealth or blessing through spoken declarations. Both strip the word of divine agency and replace it with human power, which is precisely the idolatry they unknowingly describe.
• 1 John 1:2 — "the life was made manifest, and we have seen it, and testify to it..."
• John 14:21 — "...and I will love him and manifest myself to him."
• 1 Corinthians 12:7 — "To each is given the manifestation of the Spirit for the common good."
• 1 Timothy 3:16 — "He was manifested in the flesh, vindicated by the Spirit, seen by angels..."
• Romans 1:19 — "For what can be known about God is plain to them, because God has shown [manifested] it to them."
G5319 phaneroō — to make visible, to reveal, to manifest; used extensively of the Incarnation and of God's self-disclosure; root of "epiphany."
G602 apokalupsis — revelation, uncovering; often translated "revelation" — the making manifest of what was hidden.
• "God did not leave us to guess at his character — he manifested himself fully in the Person of Jesus Christ."
• "The works of the Holy Spirit in the church are manifestations of the Kingdom — visible signs of invisible realities."
• "What was hidden in types and shadows in the Old Testament is fully manifested in Christ: he is the end toward which all the Law and Prophets pointed."