'Diligently' in the Bible

Only be strong and very courageous {to observe diligently the whole law} that Moses my servant commanded you. Do not turn aside from it, [to] the right or left, so that you may succeed {wherever you go}.

The scroll of this law will not depart from your mouth; you will meditate on it day and night so that {you may observe diligently all that is written} in it. For then you will succeed [in] your ways and prosper.