the heavens. Put by Figure of speech Metonymy (of Subject), for God, Who dwells there.
tongue walketh. Figure of speech Prosopopoeia.
earth. Supply the Ellipsis, by adding "[they say]". "Let His People return hither" as in Psalms 73:10.
Related Commentaries of Psalms 73:9
Psalms 73:9
9 They set their mouth against the heavens, and their tongue walketh through the earth.