What Am I?

[63 words]

The normal lifespan we far exceeded
Because we were so badly needed.
Though made by mortal man
We were used in God’s plan.
Some of us were stepped upon
But we never complained or groaned.
We were all essential every day
We served right well the whole way.
We literally covered God’s nation
As they went from station to station.
What am I?

(Answer in Deuteronomy 29:5)