To "have no spine" is to have no courage, resolve, or strength of character.
To "grow a spine" is to become confident or courageous; to be emboldened.
To "show some spine" is to demonstrate determination, resolve, and strength of character.
Deu 28:13
The LORD will make you the head and not the tail, and you will always end up at the top and not at the bottom, if you obey his commandments which I am urging you today to be careful to do.
