'Unyielding' in the Bible

a defiant nation who will have no respect for the old, nor show favor to the young,

The Lord is their [unyielding] strength,And He is the fortress of salvation to His anointed.

The Lord will give [unyielding and impenetrable] strength to His people;The Lord will bless His people with peace.

On God my salvation and my glory rest;He is my rock of [unyielding] strength, my refuge is in God.