Musar for Joshua 1:7

רַק֩ חֲזַ֨ק וֶֽאֱמַ֜ץ מְאֹ֗ד לִשְׁמֹ֤ר לַעֲשׂוֹת֙ כְּכָל־הַתּוֹרָ֗ה אֲשֶׁ֤ר צִוְּךָ֙ מֹשֶׁ֣ה עַבְדִּ֔י אַל־תָּס֥וּר מִמֶּ֖נּוּ יָמִ֣ין וּשְׂמֹ֑אול לְמַ֣עַן תַּשְׂכִּ֔יל בְּכֹ֖ל אֲשֶׁ֥ר תֵּלֵֽךְ׃

Only be strong and very courageous, to observe to do according to all the law, which Moses My servant commanded thee; turn not from it to the right hand or to the left, that thou mayest have good success whithersoever thou goest.

Mesilat Yesharim