Synergism in salvation theology holds that both God and the human will cooperate in the act of conversion and regeneration. The exact nature of that cooperation varies across traditions: Semi-Pelagianism held that fallen man takes the initial step toward God and grace assists; Arminianism holds that prevenient grace restores the freedom to accept or reject, making genuine response possible; Roman Catholicism teaches that infused grace and meritorious human works cooperate to justify and sanctify. All synergist systems share a core conviction: that the human will, at some point, contributes an act that is a necessary condition of salvation — not merely a consequence of it. This is contrasted with monergism (the Reformed/Calvinist view), which holds that God alone acts in regeneration, and human faith itself is a gift wrought entirely by God. The key exegetical battleground is texts like John 6:44, Ephesians 2:8–9, and Philippians 2:12–13.
SYN'ERGY, n. [Gr. συνεργία.] The combined or correlated action of different organs or parts, producing a result greater than any single part could produce alone. In theology, synergism denotes the cooperation of the human will with divine grace in the process of regeneration and conversion. Opposed to monergism.
• Philippians 2:12–13 — "Work out your own salvation with fear and trembling, for it is God who works in you, both to will and to work for his good pleasure." — Both human working and divine working affirmed simultaneously.
• John 6:44 — "No one can come to me unless the Father who sent me draws him." — Monergists cite this as proof that the will cannot cooperate until God first acts decisively.
• Acts 16:14 — "The Lord opened her heart to pay attention to what was said by Paul." — God's prior act enables Lydia's response.
• Romans 8:7 — "The mind that is set on the flesh is hostile to God, for it does not submit to God's law; indeed, it cannot." — The monergist's key text on the inability of the natural will.
• 2 Corinthians 6:1 — "Working together [synergountes] with him, then, we appeal to you not to receive the grace of God in vain." — The language of working-together in the apostolic mission.
G4904 — synergos (συνεργός): fellow worker, co-laborer. Used by Paul of his missionary companions: "God's fellow workers" (1 Cor 3:9), implying human agency within divine work.
G4903 — synergeō (συνεργέω): to work together with, to cooperate. Used in Romans 8:28 — "all things work together for good."
The danger in all synergist systems is the subtle inflation of human contribution in salvation — and with it, the subtle deflation of grace. If the human will must "cooperate" for regeneration to occur, then ultimately the distinguishing factor between the saved and the unsaved is something in the saved person, not in God's sovereign choice. This undermines the biblical teaching that salvation is "not of him who wills, nor of him who runs, but of God who shows mercy" (Romans 9:16). Synergism is not always heresy — Arminianism affirms salvation by grace through faith alone — but it tends toward a man-centered gospel if unchecked. The Reformation battle-cry was sola gratia precisely because the medieval church had drifted into meritorious cooperation theology.