New Defender's Study Bible Notes
31:6 strong and of a good courage. This is the first of ten admonitions in the Bible to be strong and courageous. The second is in the next verse. See also Joshua 1:7, etc. The last is by David to Solomon (I Chronicles 28:20).
31:8 will not fail thee. Compare this phrase to Joshua 1:5,9, and Hebrews 13:5.