Joshua 1:8 - Meditation plus Obedience equals Success

Josh 1:8 (NLT)  Study this Book of the Law continually. Meditate
on it day and night so you may be sure to obey all that is written
in it. Only then will you succeed.

Joshua was to do three things with regard to the Scriptures:
(a) The Law was not to depart from his mouth; he was to talk
about it;
(b) He was to meditate on it day and night, to think about it;
(c) He was to do everything written in it, to obey its commands
fully and to act by it.
[Bible Knowledge Commentary]

Created in God's image, we were formed to live in harmony with
God's laws. Obedience to them assures both physical and spiritual
success. [SDA Commentary]

Total obedience to all the law, which is to be the focus of the
people's thinking day and night. Only by this discipline can the people
survive and be assured of God's presence wherever [they] go. [Cambridge
Annotated SB]

To know God's revealed Word requires reading it daily and
relying on the strength of God's presence to practice the Word.
[Disciple SB]

This command is based on God's power through His Word. [Bible
Knowledge Commentary]

How strange to equate success with obedience.  For many, success
is controlling others; for Joshua it meant being controlled by God.
 God told Joshua that to succeed he must obey the rules for
living found in God's law.  Often we can't see what the results or
future benefits of following God will be.  When we are not sure what to
do, obedience to what God has revealed in the Scriptures is the only
sure step we can take.  Resolve to set aside time each day to read
and think about God's word.  Remind yourself of God's words day and
night.  Act today on what you know God has said, and God will assure
your success in carrying out his purposes.  [Life Application SB]

Notice that courage is demanded in the Christian life (vv. 6-7,
9), but this courage is supplied by the Word of God (v. 8). [Wiersbe
Expository Outlines]

The Way Of Success: A successful mission in the service of the
Lord is dependent upon courage, meditation, and obedience. Joshua was
instructed by God to be strong and courageous. His was not an easy task,
for he not only had to confront the ungodly inhabitants of the
Promised Land, but he would have to provide leadership for his own
fearful and complaining people.
He was told to do all that was required in the Law. He was not
to turn from it either to the right or the left. This would not be
easy. It never is. It can only be accomplished by constant meditation
day and night. By meditating in the Word of God, that Word becomes
established in our hearts and minds. It molds our character and guides our
If we are careful to do all that is written, then our way will
be prosperous and we will have success. [Daily Devotional Bible]