Judges 16:6

Where lies the secret strength of faith? It lies in the food it feeds on; for faith studies what the promise is—an emanation of divine grace, an overflowing of the great heart of God. Faith says, "My God could not have given this promise, except from love and grace; therefore, it is quite certain His Word will be fulfilled."

Then faith thinks, "Who gave this promise?" It considers not so much its greatness, as, "Who is the author of it?" She remembers that it is God who cannot lie—God omnipotent, God immutable—and therefore concludes that the promise must be fulfilled; and she advances forward in this firm conviction.

She remembers why the promise was given—namely, for God’s glory. She feels perfectly sure that God’s glory is safe, that He will never stain His own honor, nor mar the splendor of His own crown; and therefore the promise must and will stand.

Then faith also considers the amazing work of Christ as being a clear proof of the Father’s intention to fulfill His word.

"He that spared not his own Son, but freely delivered him up for us all, how shall he not with him also freely give us all things?"

Moreover, faith looks back upon the past, for her battles have strengthened her, and her victories have given her courage. She remembers that God never has failed her; no, He never once failed any of His children.

She recollects times of great peril, when deliverance came; hours of awful need, when her strength was found to match her day. And she cries, "No, I never will be led to think that He can change and leave His servant now. Until now the Lord has helped me, and He will still help me."

Thus faith views each promise in its connection with the promise-giver, and, because she does so, can with assurance say, "Surely goodness and mercy shall follow me all the days of my life!"