John 17:3, NLT: "And this is the way to have eternal life--to know you, the only true God, and Jesus Christ, the one you sent to earth." 
Jesus explicitly states that he is not God.Jesus is saying that 
the Father is the only true God.
Jesus is not God and Holy spirit too. 
We Can clearly see that Jesus Christ giving someone the title of “ONLY TRUE GOD” that means jesus himself is not GOD but christians worship jesusJesus always referred to himself as having been sent by God, meaning that he was a Divine messenger. For instance:This is Eternal Life: to know you the only true God, and Jesus Christ whom you have sent (John 17:3)
Jesus Christ whom you have sent (John 17:3)I can of my own self do nothing, as I hear I judge and my judgement is just; because I seek not my own will, but the will of the Father which has sent me (John 5:30)
the Father which has sent me (John 5:30)And the Father Himself, which has sent me, has borne witness of me. (John 5:37)
the Father Himself, which has sent me, has borne witness of me. (John 5:37) He never said he was God, but that God sent him, and indicates that he and God are not the same.Jesus (pbuh) said, “The Father is greater than I.” [John 14:28]
“The Father is greater than I.” [John 14:28]Jesus (pbuh) said, “The father is greater than all.” [John 10:29]
“The father is greater than all.” [John 10:29]“Truly, truly, I say to you, a slave is not greater (meizon) than his master, nor is One who is sent greater (meizon) than the one who sent him.” [John 13:16]
One who is sent greater (meizon) than the one who sent him.” [John 13:16]For instance in John 17:3 he says and this is life eternal. This is the way to eternal life that they may know you the original God or true God and Jesus Christ who you have sent as your messenger. The Quran confirms that Jesus called for the worship of the Only True God:
“Truly, God is my Lord and your Lord, so worship Him (alone).This is the straight path.” (Quran 3:51)