John 3:16-18 [NIV]
16 For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life. 17 For God did not send his Son into the world to condemn the world, but to save the world through him. 18 Whoever believes in him is not condemned, but whoever does not believe stands condemned already because they have not believed in the name of God’s one and only Son.
So just putting my money where my mouth is and starting it off with a defense of the OP.
Believe is not just said once, but several times in this chapter
John 3
15 That whosoever
believes in him should not perish, but have eternal life.
16 For God so loved the world, that he gave his only begotten Son, that whosoever
believes in him should not perish, but have everlasting life.
17 For God sent not his Son into the world to condemn the world; but that the world through him might be saved.
18 He that
believes on him is not condemned: but he that
believes not is condemned already, because he has not believed in the name of the only begotten Son of God.
19 And this is the condemnation, that light is come into the world, and men loved darkness rather than light, because their deeds were evil.
20 For everyone that does evil hates the light, neither comes to the light, lest his deeds should be exposed.
21 But he that does truth comes to the light, that his deeds may be made manifest, that they are worked in God.
22 After these things came Jesus and his disciples into the land of Judea; and there he tarried with them, and baptized.
23 And John also was baptizing in Aenon near to Salim, because there was much water there: and they came, and were baptized.
24 For John was not yet cast into prison.
25 Then there arose a question between some of John's disciples and the Jews about purifying.
26 And they came unto John, and said unto him, Rabbi, he that was with you beyond Jordan, to whom you bear witness, behold, the same baptizes, and all men come to him.
27 John answered and said, A man can receive nothing, except it be given him from heaven.
28 You yourselves bear me witness, that I said, I am not the Christ, but that I am sent before him.
29 He that has the bride is the bridegroom: but the friend of the bridegroom, who stands and hears him, rejoices greatly because of the bridegroom's voice: this my joy therefore is fulfilled.
30 He must increase, but I must decrease.
31 He that comes from above is above all: he that is of the earth is earthly, and speaks of the earth: he that comes from heaven is above all.
32 And what he has seen and heard, that he testifies; and no man receives his testimony.
33 He that has received his testimony has set his seal to this that God is true.
34 For he whom God has sent speaks the words of God: for God gives not the Spirit by measure unto him.
35 The Father loves the Son, and has given all things into his hand.
36 He that
believes on the Son has everlasting life: and he that
believes not the Son shall not see life; but the wrath of God abides on him.
KJ2000