Faith beholds and is transformed. Flesh is ever counting steps and measuring distances. Calculating how far he has come, and how far he must go.
The reason God's children in the desert could never enter the promised land is because they gave more regard to the giants, the enemies and the obstacles they faced than the word of Him who made the promise.
They saw firsthand how, through Moses, the God of Abraham, Isaac and Jacob displayed signs and wonders and a great deliverance out of the nation of Egypt. But they could not make the transition to believing that the same one who delivered them with a mighty arm and an outstretched hand would continue to perform great wonders for them - that they could still trust his word.
So they walked in circles for forty years pining for leeks and singing, ’How Great Thou Art.’ Until at last they expired without ever entering God's promises.