No, not quite right. The phrase is actually God’s peed. More about evacuation than velocity!

A great spell to banish constipation. "People often say "god speed" as a way of wishing you a fast passage of something...."

Of course it could simply be the old Viking English word.
In Norwegian good is actually god, so god speed would be a wish for you not to be delayed.
How mundane!

I believe you may be right for this reason:
speed equals distance divided by time, so god speed is the distance to god divided by the time taken to reach god
According to Christian tenets God is omnipresent and so is zero distance from anything and everything taking zero time to reach it 0/0= 0 god speed
According to Einstein matter dilates the closer it gets to light speed ( C ) at which point it becomes energy
If ( c ) is the maximum speed and (0) is the total absence of speed then it is likely that (0) is the point where energy coalesces back in to matter that is absolutely stationary.
Something a god speed would not move at all, and the rotating universe would fly past it and leave it behind.

Maybe it's a misprint and should have read "God's peed" and the road is therefore muddy, so you are advised to fly.