17 Heb “they set in heaven their mouth, and their tongue walks through the earth.” The meaning of the text is uncertain. Perhaps the idea is that they lay claim to heaven (i.e., speak as if they were ruling in heaven) and move through the earth declaring their superiority and exerting their influence. Some take the preposition -בְּ (bet) the first line as adversative and translate, “they set their mouth against heaven,” that is, they defy God.
18 Heb “therefore his people return [so Qere (marginal reading); Kethib (consonantal text) has “he brings back”] to here, and waters of abundance are sucked up by them.” The traditional Hebrew text () defies explanation. The present translation reflects M. Dahood’s proposed emendations (Psalms [], 2:) and reads the Hebrew text as follows: לָכֵן יִשְׂבְעוּם לֶחֶם וּמֵי מָלֵא יָמֹצּוּ לָמוֹ (“therefore they are filled with food, and waters of abundance they suck up for themselves”). The reading יִשְׂבְעוּם לֶחֶם (yisvé’um lekhem, “they are filled with food”) assumes (1) an emendation of יָשׁיּב עַמּוֹ (yashyyv, “he will bring back his people”) to יִשְׂבְעוּם (yisvé’um, “they will be filled”; a Qal imperfect third masculine plural form from שָׂבַע [sava’] with enclitic mem [ם]), and (2) an emendation of הֲלֹם (halom, “to here”) to לֶחֶם (“food”). The expression “be filled/fill with food” appears elsewhere at least ten times (see Ps 132:15, for example). In the second line the Niphal form יִמָּצוּ (yimmatsu, derived from מָצָה, matsah, “drain”) is emended to a Qal form יָמֹצּוּ (yamotsu), derived from מָצַץ (matsats, “to suck”). In Isa 66:11 the verbs שָׂבַע (sava’; proposed in Ps 73:10a) and מָצַץ (proposed in Ps 73:10b) are parallel. The point of the emended text is this: Because they are seemingly sovereign (v. 9), they become greedy and grab up everything they need and more.
19 Heb “How does God know? Is there knowledge with the Most High?” They appear to be practical atheists, who acknowledge God’s existence and sovereignty in theory, but deny his involvement in the world (see Pss 10:4, 11; 14:1).

In other versions

ESVEnglish Standard Version

They set their mouths against the heavens,

and their tongue struts through the earth.

Therefore his people turn back to them,

and find no fault in them.

And they say, “How can God know?

Is there knowledge in the Most High?”

NIVNew International Version (2011)

Their mouths lay claim to heaven,

and their tongues take possession of the earth.

Therefore their people turn to them

and drink up waters in abundance.

They say, “How would God know?

Does the Most High know anything?”

CSBChristian Standard Bible

They set their mouths against heaven,

and their tongues strut across the earth.

Therefore his people turn to them

and drink in their overflowing words.

The wicked say, “How can God know?

Does the Most High know everything?”

NLTNew Living Translation

They boast against the very heavens,

and their words strut throughout the earth.

And so the people are dismayed and confused,

drinking in all their words.

“What does God know?” they ask.

“Does the Most High even know what’s happening?”

LEBThe Lexham English Bible

They set their mouth against the heavens,

and their tongue roams the earth.

Therefore his people turn there,

and abundant waters are slurped up by them.

And they say, “How does God know?”

and, “Does the Most High have knowledge?”

KJV 1900King James Version

They set their mouth against the heavens,

And their tongue walketh through the earth.

Therefore his people return hither:

And waters of a full cup are wrung out to them.

And they say, How doth God know?

And is there knowledge in the most High?

Public Domain