The Creator, blessed be His name, knows all of man’s deeds and thoughts.”He who molded every heart together, He understands what each one does.” (Psalm 33:15.)
The Tenth principle asserts our belief that the Creator knows all the thoughts and actions of man. HaShem is all-knowing, or omniscient i.e., He knows everything.
His knowledge, obviously, is completely unlike our knowledge. We ‘acquire’ knowledge (now I don’t know, now I do ) while His knowledge is not something that can be separated from His essence (there is not such a thing as ‘God knows now something He ignored before’)…He and His knowledge … are One… This concept is beyond the power of speech to express, and beyond the power of the ear to hear. There is no way the human mind can comprehend it” (Maimonides MT, Yesode haTora 2:10).
Man cannot understand the nature of God’s knowledge, i.e., how God knows what we are thinking or feeling, or how His knowledge of the future does not compromise our freedom of choice, etc. As the prophet Yesha’ayahu said (55:8): “My thoughts [=God’s thoughts] are not your thoughts, My ways are not your ways”.
What we do understand about God’s knowledge, and which concerns us the most, is that God knows us intimately.
In the words of Rabbi Hayim Pereira-Mendes : “Whatever we do or say or think, God knows it. It is useless for us to try and deceive God by false excuses. God knows our thoughts. God knows what conduct should be expected of us by reason of our intelligence or education or environment. The greater our intelligence, the better our education, the more enlightened our environment, the higher are the ideals of conduct expected from us by God…. God has given us the power of discerning between right and wrong. He knows that we possess that power. Therefore we must use it rightly and wisely.”
Beyond its philosophical value, this principle signals primarily our ethical responsibility: we must live a life with the consciousness that God knows our thoughts, actions and intentions. We might easily deceive other human beings. Hide our negative intentions or secrets plans behind eloquent words, rhetoric or gestures. But when it comes to God, there are no lies, excuses or pretensions. The more we become alert of God’s omniscience, the easiest to live a life of righteousness. And vice-versa.
The Shulhan ‘Arukh (or more precisely, the glosses of Rabbi Moshe Isserles, 1520-1572, or MURAM) in the first article of the first chapter, explains this idea deeper. He implies that having HaShem present and realizing that nothing is hidden from His sight, protects us from ourselves, “As it is said in Tehillim: “I’m aware of [lit. I put] HaShem’s [Presence] always in front of me. ” This is a greatly important concept in the Tora, and it is the fundamental quality of the tsadiqim (righteous people) who conduct themselves on the paths of HaShem. Since the way a person conducts himslef … and performs his daily activities while alone at home is not the same as when he is in front of a sovereign. In addition, the way a person talks or expresses himself, while in the privacy of his home …is not the same as when he would address a mortal king. Then, when one sets in his mind that the Almighty King, the Holy One, blessed He is, is in front of him… then, if a person is about to do something wrong, even privately, the thought of knowing that Hashem is seeing us… will make a person feel ashamed before God, and he will not do any wrong… “