Psalms 50:6

Better (unless we alter the vocalisation and render, and let the heavens declare),

And the heavens declare his righteousness,

For God is about to Judge.

While the defendants are being gathered, the Psalmist hears the heavens, which have been summoned to witness the trial, solemnly proclaiming the justice of the Judge, as a guarantee of the impartiality of His judgement. This explanation is supported by the use of the perfect tense in Psalms 97:6, a passage which is obviously based upon this Psalm.