Call to inanimate nature to praise God; for it also shall share in the coming deliverance from “the bondage of corruption” (Rom 8:20, Rom 8:21).
done it - effected redemption for both the literal and spiritual Israel.
lower parts, etc. - antithetical to “heavens”; “mountains,” “forest,” and “tree,” are the intermediate objects in a descending gradation (see Psa 96:11, Psa 96:12).