Jesus said "I and my Father are one" (John 10:30). Jesus, also called the "Word," existed with God from the beginning, and actually was the Creator as explained in John 1:1-3: "In the beginning was the Word, and the Word was with God, and the Word was God. 2. The same was in the beginning with God. 3. All things were made by him; and without him was not any thing made that was made." Ephesians 3:9, Colossians 1:16, Hebrews 1:2 and many other verses also clearly explain this.
For several reasons (and according to God's plan, Rev. 13:8) the Word was made human in the form we know as Jesus: "And the Word was made flesh, and dwelt among us" (John 1:14). The apostle Paul wrote that God "Hath in these last days spoken unto us by his Son, whom he hath appointed heir of all things, by whom also he made the worlds" (Hebrews 1:2). Jesus said of His mission to mankind: "the Father which sent me, he gave me a commandment, what I should say, and what I should speak" (John 12:49). Jesus explained "For I am come down from heaven, not to do mine own will, but the will of him that sent me" (John 6:38). Jesus "went throughout every city and village, preaching and showing the glad tidings of the kingdom of God" (Luke 8:1).
Jesus' sacrificial death paid the penalty (which is death, see Romans 6:23) for our sin, thus providing for our redemption to God and making possible our reconciliation to God if we repent.
After His resurrection Jesus appeared to His disciples: "And Jesus came and spake unto them, saying, All power is given unto me in heaven and in earth" (Matthew 28:18). Jesus now has full control over all creation, and has been authorized to judge all men. We can relate to Jesus as we would to God the Father: Jesus has the power of God over us.