John 3:3-5 says, “Jesus answered and said to him, ‘Most assuredly, I say to you, unless one is BORN AGAIN, he cannot SEE the kingdom of God.’ Nicodemus said to Him, ‘How can a man be born when he is old? Can he enter a second time into his mother’s womb and be born?’ Jesus answered, ‘Most assuredly, I say to you, unless one is BORN OF WATER AND THE SPIRIT, he cannot ENTER the kingdom of God.’” Before we seek to answer your question directly, it is vital to see that ONE MUST BE BORN AGAIN in order to “see and enter the kingdom of God.” Being “born again” is required for both. So, what does it mean to be born again? Nicodemus was confused and thought it meant a “literal second birth from his mother’s womb.” But Jesus corrected that thought by saying, “That which is BORN OF THE FLESH is flesh, and that which is BORN OF THE SPIRIT is spirit.” In other words, when one is “born of the flesh” it is a “physical birth,” but when one is “born of the Spirit” it is a “spiritual birth.” The physical birth results in one being born in sin (see Psalm 51:5), the spiritual birth results in one receiving a new life in the family of God (see John 1:12-13). The physical birth does not enable a person to “SEE the kingdom of God” or to “ENTER the kingdom of God.” The spiritual birth enables a person to SEE and ENTER the kingdom of God.

Now, what the difference is between SEEING and ENTERING the kingdom of God. In fairness, some Bible commentators see no difference and thus they believe they are two words with the same meaning; in other words, they are synonymous. I do believe there is a difference, though they are vitally connected. To use a simple illustration, if one is standing 10 feet away from a beautiful lake, he can SEE the lake (and admire its beauty), but he has not ENTERED the lake until he steps into it. I believe the Lord mentioned “seeing” first because the moment one is born of God, they then have the “spiritual sight” to see what God’s kingdom is like from afar (through the truth revealed in Scripture). In Acts 26:17-18 Jesus said to Saul (who was later named Paul), “I will deliver you from the Jewish people, as well as from the Gentiles, to whom I now send you, to OPEN THEIR EYES, in order to TURN THEM FROM DARKNESS TO LIGHT, and from the power of Satan to God.” The apostle Paul went throughout the Roman Empire preaching the gospel of Jesus Christ and when a soul believed the gospel their “eyes were opened” to see “the light of God’s truth.” Paul was simply a messenger, but the Word of God was used by the Spirit of God to give those who believed eternal life and spiritual sight. They were “born again” by the “water and the Spirit” (the water symbolizing the Word of God; see John 15:3, Ephesians 5:26; 1st Peter 1:23)). They were no longer “spiritually blind” (see Ephesians 4:18) and had the ability to understand all the blessings of the kingdom that God has revealed in His Word (see 1st Corinthians 2:9-16).

Regarding “ENTERING the kingdom” there are “two sides of the kingdom,” the “earthly kingdom” that will be established when Christ comes as King of kings to reign for 1,000 years (see Revelation 19:11-20:4), and the “heavenly kingdom” which is already established. Nicodemus knew nothing about the heavenly kingdom so the words of Jesus were meant to teach him that before the Jews can “ENTER into Messiah’s Millennial kingdom” they must be born again (see Ezekiel 36:22-30). But during this Church Age, the moment a sinner believes the gospel he/she is born again and “ENTERS the heavenly kingdom.” We see this in Colossians 1:12-14 where Paul prayed, “Giving thanks to the Father who has qualified us to be partakers of the inheritance of the saints in the light. He has delivered us from the power of darkness and CONVEYED US INTO THE KINGDOM OF THE SON OF HIS LOVE, in whom we have redemption through His blood, the forgiveness of sins.”  

I hope the scriptures quoted/cited will prove to be helpful. As I mentioned, there are other views so I would avoid being dogmatic, but I am persuaded in my mind that this is the truth of God.  (DO)  (590.1)