Did you notice (in the NASB) the grammatical connection between [1Peter] verses 6 and 7? “Humble yourselves, therefore, under the mighty hand of God, that He may exalt you at the proper time, 7 casting all your anxiety upon Him, because He cares for you.” It’s not merely a new sentence. It’s a subordinate clause.
“Humble yourselves . . . casting your anxieties on him.”
I think this means that casting your anxieties on God is an expression of humility. It’s like saying,
- “Eat politely . . . chewing with your mouth shut.”
- “Drive carefully . . . keeping your eyes open.”
- “Be generous . . . inviting someone over on Thanksgiving.”
- “Humble yourselves . . . casting your anxieties on God.”
One way to be humble is to cast your anxieties on God. Which means that one hindrance to casting your anxieties on God is pride. Which means that undue worry about your future is probably a form of pride.