Be strong and of good courage; for you shall cause this people to inherit the land which I swore to their fathers to give them.
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. 