The Lord Jesus Christ is the one God of heaven and earth.
"And the Lord shall be King over all the earth: in that day it shall be the Lord is one and His name one." (Zechariah 14:9)
The nature of God
The essence of God is pure love and wisdom. He is eternally compassionate and forgiving, and wishes to bestow as much love on us as we are willing to receive. His love manifests in the desire to draw us closer towards Him and infuse our lives with the joy which results from this relationship. His wisdom is the means by which His love is realized.
There is one God who goes by many names. A story in the Old Testament tells of God presenting Himself to Moses as the 'I Am'. His self-given name in this story expresses the essence of His identity: He is the beginning and the end of all things — the Divine Consciousness that gives life to the universe. Knowing that the current of God's love runs through all that is, we are reminded that He is fully present in our lives, overseeing every moment, regardless of how seemingly insignificant it may be to us.
God is both fundamentally divine and human
There are not three gods, nor three persons in one God, but rather one God with three aspects to His being. Just as we all have a soul, a body and the actions of our lives (and are one person), so it is with God. The Father, Son, and Holy Spirit are names given for the soul, body and activity of the Lord God Jesus Christ.
The Holy Spirit corresponds to the Lord's activity in the world. The New Church teaches that the Lord has a divine design in all that He creates. The nature of this order is laid out in the Writings of Emanuel Swedenborg as the rules of Divine Providence. The goal and purpose of Divine Providence is to create heaven from the human race and to allow each human being to live a life that leads towards heaven. Everything that the Lord does is in service of this goal. He leaves us in our freedom to make decisions that will either lead us closer to or further away from His love. This freedom is one of his greatest gifts to us, for it enables us to choose our own life-paths.