Someone who loves God will be thankful for what they have. Dwelling on ones past losses is an unhealthy fetter.
You know The Ultimate Reality exists, and even knowing what that means you can discern rightly that God is to a great extent incomprehensible.
But we know God exists because of The Truth that is incarnate and witnessed in creation. We know that to a certain extent, we all have the ability to discern between right and wrong, truth and falsehood. It is built into us. The truth is, this sense can be trained and honed.
The orthodox discipline, and the historical Christian discipline is centered around purifying and honing this sense. We don't do this alone. Isolation very easily leads to pride is the root of much spiritual delusion. Even hermits take wise council and partake in eucharistic liturgy.
The law of Moses was created as a guideline. If the intent of the law is lost, all you have is the law itself. Fulfilling the law by letter is in itself not what makes someone righteous.
The law of Moses is a type and shadow of God's Law, which is Truth, and governs the universe. That is why we say Jesus Christ is the fulfillment of The Law and The Prophets, because Christ is The Divine wisdom that The Law is a shadow of.