Effectual call

See CALL.

Effectual prayer

Occurs in Authorized Version, James 5:16. The Revised Version renders appropriately: "The supplication of a righteous man availeth much in its working", i.e., "it moves the hand of Him who moves the world."

Noah Webster's New International Dictionary of the English Language

(a.) Adequate; sufficient to produce a desired effect; as, an effectual writing method; efficient; operative; decisive.