Faith Makes Things Possible, Not Easy

Be strong and of a good courage; be not afraid, neither be thou dismayed. Joshua had long since signalized his valour, in the war with Amalek, and in his dissent from the report of the evil spies; and yet God sees fit thus to inculcate this precept upon him. Those that have grace have need to be called upon again and again to exercise grace and to improve in it. Joshua was humble and low in his own eyes, not distrustful of God, and his power, and promise, but diffident of himself, and of his own wisdom, and strength, and sufficiency for the work, especially coming after so great a man as Moses; and therefore God repeats this so often, "Be strong and of a good courage; let not the sense of thy own infirmities dishearten thee; God is all-sufficient. Have not I commanded thee?" [1.] "I have commanded the work to be done, and therefore it shall be done, how invincible soever the difficulties may seem that lie in the way." Nay, [2.] "I have commanded, called, and commissioned, thee to do it, and therefore will be sure to own thee, and strengthen thee, and bear thee out in. it." Note, When we are in the way of our duty we have reason to be strong and very courageous; and it will help very much to animate and embolden us if we keep our eye upon the divine warrant, hear God saying, "Have not I commanded thee? I will therefore help thee, succeed thee, accept thee, reward thee." Our Lord Jesus, as Joshua here, was borne up under his sufferings by a regard to the will of God and the commandment he had received from his Father, Jn. 10:18. - Matthew Henry