This quote by John Calvin comes from Day 303 in the devotional Heart Aflame:
If the faithful regain their peace of mind only when God manifests himself as their deliverer, what room is there for the exercise of faith, and what power will the promises possess? For, assuredly, to wait calmly and silently for those indications of God’s favour, which he conceals from us, is the undoubted evidence of faith. And strong faith quiets the conscience, and composes the spirit; so that, according to Paul, “the peace of God, which passes all understanding,” reigns supremely there (Phil. 4:7).
Calvin, John. (1999). Heart Aflame Daily Readings from Calvin on the Psalms. Phillipsburg, NJ: P&R Publishing Company.