b. Baptism is very much in the context. John 1:19 ff. discusses the baptism of John. Indeed, in 1:26, John the Baptist says “I baptize with water” and in 1:33, John says that Jesus “will baptize with the Holy Spirit.” This is, of course, parallel with “born of water and Spirit” (although John the Baptist speaks disjunctively – it’s water or it’s Spirit) whereas Jesus is speaking conjunctively (which is closer to the church’s traditional understanding but not how John the Baptist spoke). Immediately after the account of Jesus with Nicodemus, we read in 3:22 that Jesus and his disciples went to the countryside and baptized with water.
c. There is no evidence that the Jews thought of water as an element of or symbol for physical birth. Indeed, John’s earlier references to natural physical birth speak of being “born of blood.” John 1:12-13. In both cases, “of” is the same preposition, ‘ek. One commentator who sought evidence that the Jews used “water” to refer to physical birth came up with considerable evidence of water being a Jewish metaphor for conception, but nothing for associating water with physical birth.
d. The Greek tends to support that only one birth is in mind –
The unity of the two elements is shown by the use of the single preposition ‘ek: ‘by water and Spirit’.
On the other hand, there are good arguments that the Spirit is in mind
a. “Water” is often used in the OT to refer to the Spirit.
(Isa 44:3 ESV) For I will pour water on the thirsty land, and streams on the dry ground; I will pour my Spirit upon your offspring, and my blessing on your descendants.
(Isa 32:14-15 ESV) For the palace is forsaken, the populous city deserted; the hill and the watchtower will become dens forever, a joy of wild donkeys, a pasture of flocks; 15 until the Spirit is poured upon us from on high, and the wilderness becomes a fruitful field, and the fruitful field is deemed a forest.
(Eze 39:29 ESV) “And I will not hide my face anymore from them, when I pour out my Spirit upon the house of Israel, declares the Lord GOD.”
(Joel 2:28-29 ESV) “And it shall come to pass afterward, that I will pour out my Spirit on all flesh; your sons and your daughters shall prophesy, your old men shall dream dreams, and your young men shall see visions. 29 Even on the male and female servants in those days I will pour out my Spirit.”
“Pour out” is clearly a water metaphor.
b. In John, the Spirit is referred to as water. In John 7:37 John is explicit –
(John 7:37-39 ESV) On the last day of the feast, the great day, Jesus stood up and cried out, “If anyone thirsts, let him come to me and drink. 38 Whoever believes in me, as the Scripture has said, ‘Out of his heart will flow rivers of living water.’” 39 Now this he said about the Spirit, whom those who believed in him were to receive, for as yet the Spirit had not been given, because Jesus was not yet glorified.
Commentators are nearly unanimous that Jesus’ references to “living water” in John 4, his conversation with the Samaritan woman, are also references to the Holy Spirit.
Some object that if “water” = “Spirit,” then Jesus is saying we must be born of “the Spirit and the Spirit,” but the same objection could be lodged against Isa 44:3, where the prophet uses “water” as a poetic metaphor for Spirit in parallel. Perhaps Jesus is borrowing the prophets’ metaphor in a similar Hebraic parallelism.
Or Jesus’ phrase could be a hendiadys, a figure of speech common in koine Greek in which two nouns or two verbs are joined by “and” with the intention that they be read as a single noun or verb. One author gives a couple of examples –
Webster’s defines this figure well: “the expression of an idea by the use of two usually independent words connected by ‘and’ (“nice and warm”) instead of the usual combination of an independent word and its modifier (“nicely warm”). In Hendiadys the two words are the same part of speech (i.e., two nouns, two verbs, etc.), and if they are nouns, they are always in the same case. The figure Hendiadys places equal emphasis on both words conjoined by the “and,” whereas if the concept was rendered literally, such as “nicely warm,” the emphasis of the phrase is on the noun, not the modifier. …
Isaiah 1:13 (NIV)
Stop bringing meaningless offerings! Your incense is detestable to me. New Moons, Sabbaths and convocations—I cannot bear your evil assemblies.
The Hendiadys in the last phrase of this verse has made it hard to translate, but the meaning is clear, and the NIV has done a superb job of bringing that meaning into English: The last phrase is rendered more literally in the ESV: “I cannot endure iniquity and solemn assembly.” God usually desires solemn assemblies, but in this case the people were so evil that the solemn assemblies they held were corrupted and evil. The figure Hendiadys recognizes and emphasizes that the people were holding assemblies, but also emphasizes that those assemblies were wicked.
Luke 21:15 (ESV)
“for I will give you a mouth and wisdom, which none of your adversaries will be able to withstand or contradict.”
It is obvious that this verse is a figure of speech, because everyone has a mouth and therefore has no need for God to give them one. Actually, there are a couple figures of speech in this verse, and we will unpack them one at a time. “A mouth and wisdom” is the figure Hendiadys for “a wise mouth,” but the figure is better than the literal statement because saying someone has a “mouth” places emphasis on the fact that there will be much speaking. Someone may have a “wise mouth” but not say much, but someone who has a “mouth” says a lot. This is one of the instances where the literal expression “mouth and wisdom” and the figurative expression “wise mouth” are both true. God will inspire much speaking and give wisdom to the speaker as well. Perhaps, “I will give you a mouth, indeed, a wise mouth,” would be a good rendition. Also, “mouth” is not literal, but is put by the figure Metonymy for the words spoken by the mouth, so in teasing out the figures a little further, a good translation might be: “I will give you (many) words, indeed, wise words.”
Thus, “water and Spirit” could mean “the Spirit, indeed, the Spirit that is the water of prophecy.” Or it could be “water that is Spirit,” consistent with Isaiah’s use and the usage of several other OT prophets. Jesus would be using “water” to be certain Nicodemus recalled the many OT passages that speak of the Spirit as water to be poured out from heaven when the Kingdom arrives.
This interpretation nicely sets the stage for “living water” in the very next chapter, which would otherwise not be defined until three chapters later.
 Paraphrased in the NIV as “born of human descent.” The KJV has “born … of blood.”
 Leon Morris, The Gospel According to John, The International Commentary on the New Testament (Grand Rapids: Eerdmans Publishing Co., 1971), 216-217. “In due course I turned away from the view that the water is simply the amniotic fluid that flows away during the process of birth, because I could find no ancient text that spoke of birth as ‘out of water.’” See also D. A. Carson, Exegetical Fallacies (Boston: Baker Book House, Inc., 1996), 41.
 Beasley-Murray, 230.
 Guy N. Woods, in his 1989 commentary on the Gospel of John in the Gospel Advocate commentary series argues that “living water” refers to the word of God, even though John himself says “living water” refers to the Holy Spirit.
 “Figures of Speech – Hendiadys (Two for One),” Truth or Tradition? http://www.truthortradition.com/articles/figures-of-speech-hendiadys-two-for-one.
 Leon Morris, The Gospel According to John, The New International Commentary on the New Testament, (Grand Rapids, MI: Wm. B. Eerdmans Publishing Co., 1995), 191–192.