The Oneness of God

Moses:

Hear, O Israel! The LORD is our God, the LORD is one!
You shall love the LORD your God with all your heart and with all your soul and with all your might.
  Deuteronomy 6:4-5


Jesus:

One of the scribes came and heard them arguing, and recognizing that He had answered them well, asked Him, "What commandment is the foremost of all?"
Jesus answered, "The foremost is, 'HEAR, O ISRAEL! THE LORD OUR GOD IS ONE LORD; AND YOU SHALL LOVE THE LORD YOUR GOD WITH ALL YOUR HEART, AND WITH ALL YOUR SOUL, AND WITH ALL YOUR MIND, AND WITH ALL YOUR STRENGTH.'  The second is this, 'YOU SHALL LOVE YOUR NEIGHBOR AS YOURSELF.' There is no other commandment greater than these."
 Mark 12:28-31 


Paul:

There is one body and one Spirit, just as also you were called in one hope of your calling; one Lord, one faith, one baptism, one God and Father of all who is over all and through all and in all.
 Ephesians 4:4-6

Muhammad:

Say: He is Allah, the One and Only;
Allah, the Eternal, Absolute;
He begetteth not, nor is He begotten;
And there is none like unto Him.
   Quran,  Sura 112

In all of these sayings, the most important idea is not that God is one being.  Most beings are unified, and the ancient world recognized that.  Rather, it is that God alone is supreme over the universe. There is no one like Him, no one above Him, no one beside Him, no one can take His place.  Thus, God's unity is His sufficiency and His alone-ness.  Even Christianity, with a Trinitarian notion of God, recognizes that God is one and no one else is beside Him.


It is this notion that all the monotheistic religions agree upon (as well as a few other things).   It is important so that we know that God is not at war with Himself.  God does not change.  God can't one day be replaced.  God isn't of multiple personalities.  God will never break his promises. When we see God's actions on earth, it may seem that God does have different personalities.  But we recognize that while God may repent of harm, that God remains steadfast in His purpose to do good to all.  While other spirits under God may harm, God is merciful.  While humanity, including religious leaders and practitioners, will often be faithless and hating and changeable-- they do not represent God in that way.


God is one and does not change.