righteousness [ts@daqah] is like the great ['el]
mountains [harar]; thy judgments [mishpat] are a great [rab] deep [t@howm]: O LORD [Y@hovah], thou
preservest [yasha`] man ['adam] and beast [b@hemah]. KJV-Interlinear
righteousness is like the mountains of God; your judgments are like the great
deep; man and beast you save, O LORD. ESV
Righteousness refers to the very essence and nature of God. The mountains, are in reference to a mountain of God, as opposed to the mountains of this earth.
Mountains are vast and considered to be eternal, always there, always stable, never moved from their place, and that is the concept being conveyed.
Gods essence, Gods righteousness, Gods justice, is the most stable thing in all of existence.
Just as God is eternal and everlasting, so too is His core nature, which should be obvious.
Too many religions try to deflate or water down the deities that they refer to. That makes them more human and vulnerable and attainable, and certainly more convenient when it comes to inventing ones beliefs.
But God is eternal and His nature is eternal and it never changes. God was truth in eternity past, is truth now and will always be truth forever.
His decisions, likewise are compared the vast depth of the oceans. Man cannot conceive of all that is in the depths of the oceans. Not even in our current technological society. But the concept here is that God knows all things, and how all things fit together. He has all of the facts and all of the answers, and His decisions are made accordingly.
His decisions are made based on fact and knowledge and wisdom, never on guesswork or conjecture. And the vastness of truth is always at His immediate and instant disposal, for perfect decisions.
And finally, all of life, both man and animal, remain alive not because of their individual efforts or intellect or abilities, but all things remain alive and continue in history courtesy of God.
We are all alive for no other reason, but by the grace of God, who sustains life and perpetuates life by means of His authority and character and decisions.