Therefore, if anyone is in Christ, he is a new creation; old things have passed away; behold, all things have become new.
2 Corinthians 5:17
Accepting Jesus Christ as Lord and Savior is truly clean slate. To receive salvation, God forgives us and erases our sins. Then we have a new life from scratch. All our previous life of sin must be left behind and, from now on, our habits and our speech should be different. It is a new birth, therefore, everything must be new because the old man was in the past forever.
In John 3:3 says the Lord: Jesus answered and said to him, “Most assuredly, I say to you, unless one is born again, he cannot see the kingdom of God.” It is a requirement born again to see the kingdom of God. This means that things cannot remain the same as before meeting the Lord when we are converted to Him. It is necessary to die to the old man or old woman born as a new creature, such as 2 Corinthians 5:17 says.
We must put on the new man as Ephesians 4:24 says: And that you put on the new man which was created according to God, in true righteousness and holiness. This new man is a creature of God, not ours. It is obvious that our humanity lacks justice and holiness of truth that God requires. It also demonstrates our inability to save ourselves by our own merits.
Our works are not able to make that transformation that makes us a new creation. Romans 7:6 says: But now we have been delivered from the law, having died to what we were held by, so that we should serve in the newness of the Spirit and not in the oldness of the letter. God’s grace frees us from dead works that do not lead us to see the Kingdom of God. And this grace alone is what allows us to acquire this new nature.
In Matthew 9:16-17, the Lord illustrated with two examples why should there be renewal: No one puts a piece of unshrunk cloth on an old garment; for the patch pulls away from the garment, and the tear is made worse. Nor do they put new wine into old wineskins, or else the wineskins break, the wine is spilled, and the wineskins are ruined. But they put new wine into new wineskins, and both are preserved.
When we gain salvation through our Lord Jesus Christ, even our name is new. Revelation 2:17 says: He who has an ear, let him hear what the Spirit says to the churches. To him who overcomes I will give some of the hidden manna to eat. And I will give him a white stone, and on the stone a new name written which no one knows except him who receives it.
And even heaven and earth will be new and Revelation 21:1 says: Now I saw a new heaven and a new earth, for the first heaven and the first earth had passed away. Also there was no more sea. In Christ we are new workmanship and everything will be new, leave behind all the old and new enjoy what forever. God bless you.