# every human creation
The word "creation" refers to offices that people have set up. "every human authority" or "every human institution"
# for the Lord's sake
Possible meanings are 1) that by obeying human authorities, they are obeying the Lord who established those authorities or 2) that by obeying human authorities, they will honor Jesus who also obeyed human authorities.
# the king as supreme
"the king as the highest human authority"