Adam Clarke on Psalms 89:14

Justice and judgment are the habitation of thy throne - The throne - the government, of God, is founded in righteousness and judgment. He knows what is right; he sees what is right; he does what is right; and his judgments are ever according to righteousness. His decisions are all oracles, no one of them is ever reversed.

Mercy and truth shall go before thy face - These shall be the heralds that shall announce the coming of the Judge. His truth binds him to fulfill all his declarations; and his mercy shall be shown to all those who have fled for refuge to the hope that is set before them in the Gospel. See the notes on Psa 85:10, Psa 85:11.