Those who believe that they believe in God, but without passion in their hearts, without anguish in mind, without uncertainty, without doubt, without an element of despair even in their consolation, believe only in the God idea, not in God Himself.

[Los que sin pasión de ánimo, sin congoja, sin incertidumbre, sin duda, sin la desesperación en el consuelo, creen creer en Dios, no creen sino en la idea de Dios, más no en Dios mismo.]

Miguel de Unamuno (1864-1936) Spanish philosopher and writer [Miguel de Unamuno y Jugo]

The Tragic Sense of Life [Del sentimiento trágico de la vida], ch. 9 “Faith, Hope, and Charity” (1912) [tr. Flitch (1921)]
    (Source)

Alt. trans. [tr. Kerrigan (1972)]: "Whoever believes he believes in God, but believes without passion, without anguish, without uncertainty, without doubt, without despair-in-consolation, believes only in the God-Idea, not in God Himself."

Original Spanish.

In Unamuno's earlier, unpublished work Treatise on the Love of God [Tratado del amor de Dios], ch. 3 "What is Faith?" (1905-08) [tr. Orringer], he used this same phrase and surrounding text: "Those without passion in their soul, without anguish, without uncertainty, without doubt, without despair in consolation, think they believe in God; they believe only in the idea of God, but not in God Himself."