Joshua 1:6

We may add, that not once only or by one single expression are strength and constancy required of Joshua, but he is confirmed repeatedly and in various terms, because he was to be engaged in many and various contests. He is told to be of strong and invincible courage. Although these two epithets make it obvious that God was giving commandment concerning a most serious matter, still not contented with this reduplication, he immediately after repeats the sentence, and even amplifies it by the addition of the adverb very.

From this passage, therefore, let us learn that we can never be fit for executing difficult and arduous matters unless we exert our utmost endeavors, both because our abilities are weak, and Satan rudely assails us, and there is nothing we are more inclined to than to relax our efforts. But, as many exert their strength to no purpose in making erroneous or desultory attempts, it is added as a true source of fortitude that Joshua shall make it his constant study to observe the Law. By this we are taught that the only way in which we can become truly invincible is by striving to yield a faithful obedience to God. Otherwise it were better to lie indolent, and effeminate than to be hurried on by headlong audacity.

Moreover, God would not only have his servant to be strong in keeping the Law, but enjoins him to contend manfully, so as not to faint under the burden of his laborious office. But as he might become involved in doubt as to the mode of disentangling himself in matters of perplexity, or as to the course which he ought to adopt, he refers him to the teaching of the Law, because by following it as a guide he will be sufficiently fitted for all things. He says, You shall act prudently in all things, provided you make the Law your master; although the Hebrew word שכל, means to act not only prudently but successfully, because temerity usually pays the penalty of failure.

Be this as it may, by submitting entirely to the teaching of the Law he is more surely animated to hope for divine assistance. For it is of great consequence, when our fears are excited by impending dangers, to feel assured that we have the approbation of God in whatever we do, inasmuch as we have no other object in view than to obey his commands. Moreover, as it would not be enough to obey God in any kind of way, Joshua is exhorted to practice a modesty and sobriety which may keep him within the bounds of a simple obedience.

Many, while possessed of right intention, sometimes imagine themselves to be wiser than they ought, and hence either overlook many things through carelessness, or mix up their own counsels with the divine commands. The general prohibition, therefore, contained in the Law, forbidding all men to add to it or detract from it, God now specially enforces on Joshua. For if private individuals in forming their plan of life behoove to submit themselves to God, much more necessary must this be for those who hold rule among the people. But if this great man needed this curb of modesty that he might not overstep his limits, how intolerable the audacity if we, who fall so far short of him, arrogate to ourselves greater license? More especially, however, did God prescribe the rule of his servant, in order that those who excel in honor might know that they are as much bound to obey it as the meanest of the people.