There are hints of it contained in some Old Testament oracles, but the subject is really introduced to Bible readers during the Saviour’s famous conversation with Nicodemus in John chapter 3. In considering this subject, it will be useful to look back at a key Old Testament prophecy concerning regeneration, before considering how this “mysterious” process is explained by Jesus and the apostles.
For the Old Testament background, we must particularly look to a passage from the prophet Ezekiel. Ezekiel’s oracle points forward to a time when the Lord would give His people a new heart, sprinkle clean water upon them and put His Spirit within them (Ezekiel 36:25-27). In the vision which immediately follows it, the nation of Israel is pictured as being dead, only for God to resurrect them and, once again, make the promise that He would place His Spirit in them (Ezekiel 37:1-14). Whilst these visions are solely concerned with one nation, they nevertheless anticipate what the Holy Spirit does today in the life of anyone who comes to know the Lord.
Israel’s deadness pictures the life of every person who, by nature, is under the sentence of condemnation pronounced upon Adam in Eden (Genesis 3:19). All are dead towards God on account of their sin (Ephesians 2:1-3) and, in such a condition, it is impossible for anyone to make themselves acceptable to God, given that they are completely cut off from Him. As Jesus explained to Nicodemus, flesh can only reproduce its own kind (John 3:6) and so any attempts at self-reformation will inevitably result in a furtherance of the sinful life. Consequently, only the direct intervention of God in a person’s heart can bring the necessary change that leads to eternal life. We “must be born again” (John 3:7).
Regeneration occurs in an individual through that person’s reception of the Word of God and through the work of the Holy Spirit in the heart. God’s Word is likened to seed in various New Testament passages (cp. Luke 8:4-15; 1 Peter 1:23; 1 John 3:9) and it achieves exactly the same results on the spiritual level as seed sown in the field does in the natural world: a new life is created in the new believer. All this can only be done through God’s Holy Spirit. He is the One who enables people to understand the message of the gospel and causes the seed to become fruitful (cp. 1 Corinthians 3:6). No doubt for this reason Jesus described regeneration as being born of the Spirit (John 3:5).
Just as the Lord promised to sprinkle clean water upon the nation of Israel in the Ezekiel passage, so regeneration is spoken of as a “washing” in Titus 3:5. Again, the instrumentality of both Word and Spirit in this cleansing are to be observed. We are clean because the Word of God concerning His Son is now in us (cp. John 15:3) and it is the Spirit who is said to be the One who effects this (1 Corinthians 6:11; Titus 3:5).
New birth is not an end in itself; the new life must be nurtured and allowed to grow. In the parable of the Sower (Luke 8), the seed sown in the good soil produced an abundant crop. The regenerated root results in new and living fruit in the life. Paul describes this as “the fruit of the Spirit”. The Spirit’s fruit might be defined as qualities which do not naturally occur in their fulness in human beings, but which manifest themselves in all who have been truly born again (Galatians 5:22-23). It is therefore incumbent upon all who have been born from above (John 3:3 NET) to live from then onwards in the good of the new life which they have received from God.