Joshua 1:8

Out of thy mouth — That is, thou shalt constantly read it, and upon occasion discourse of it, and the sentence which shall come out of thy mouth, shall in all things be given according to this rule. Day and night — That is, diligently study, and upon all occasions consider what is God's will and thy duty. The greatness of thy place and employments shall not hinder thee from this work, because this is the only rule of all thy private actions, and publick administrations.