'Service' in the Bible

because of this are they before the throne of God, and they do service to Him day and night in His sanctuary, and He who is sitting upon the throne shall tabernacle over them;

in the midst of its broad place, and of the river on this side and on that, is a tree of life, yielding twelve fruits, in each several month rendering its fruits, and the leaves of the tree are for the service of the nations;