TRUST

"Never look a gift horse in the mouth"
Good idea generally, gift horses can be liabilities - expensive ones.
But if G-d is giving gifts, trust Him.
He is not a horse thief

If you don't trust G-d, then you trust no one: who can you trust?
And ultimately, you don't trust trust.
How can you get on a plane, if you don't trust pilots' licensing?
How can you cross the street if you trust no one to stop on a red light?
How can you buy food that isn't poisoned?

Still, He allows you to verify his Truth.
But He doesn't advise it:
If you're lucky, you'll confirm what He told you,
If you're not lucky, you won't be wiser, but you will be miserable.

But when you get a gift, He still wants you to check it out.
See how you will use it best: Is this a broodmare or a bloodhorse colt?
The spies in our parsha went to see if they should take the gift or not.
The spies a generation later went to see how best to take the land.

Moshe added the name of G-d to Joshua's name.
Without the name of G-d, Joshua might have gotten more involved in the horse than the race. 

See how you can do the best job, not if you should take the job or not.
Look the gifts G-d gives you in the mouth. Then go win the race.