Then you will have success if you are careful to observe the decrees and laws that the LORD gave Moses for Israel. Be strong and courageous. Do not be afraid or discouraged.
NIV
Then you will prosper if you are careful to keep and fulfill the statutes and ordinances with which the Lord charged Moses concerning Israel. Be strong and of good courage. Dread not and fear not; be not dismayed.
AMP
Then shalt thou prosper, if thou takest heed to fulfil the statutes and judgments which the LORD charged Moses with concerning Israel: be strong, and of good courage; dread not, nor be dismayed.
KJV