The word paradise is used as a synonym for Heaven.
2 Corinthians 12:4, “How that he was caught up into paradise, and heard unspeakable words, which is not lawful to utter.”
Paul tells of a time when he was taken to the third heaven, whether in the body or out, he didn’t know [2 Corinthians 12:2]. He tells us very clearly, that paradise is in the third heaven [abode of God and Jesus]. Jesus came from the third heaven and went back to the third heaven at his ascension. The first heaven is the sky and atmosphere, the second heaven is the stars and planets. The third heaven is where the throne of God is.
Paradise in the Old Testament
In O.T. times the righteous dead went to paradise and the wicked dead to Hades or torments [Luke 16:19-31]. There was a great gulf fixed between the two. Hades was divided into a place of comfort [Paradise], and a place of torments.
Paradise in the New Testament
Jesus, after his resurrection, took the departed souls of believers from paradise into the third heaven [Acts 2:27, 31; Eph. 4:9]. Also, after the resurrection of Christ, believers no longer go to paradise below, but to paradise above, into the presence of the Lord in the third heaven [Luke 23:24; 2 Cor. 12:2-4; Rev. 2:7]. Today, when a believer dies, he is “present with the Lord” in the third heaven in paradise [2 Cor. 5:6-9].
The final state of the righteous and wicked
Believers will one day abide in the New Jerusalem on the new heavens and the new earth [Rev. 21-22]. The wicked will be taken out of Hades and cast into the Lake of Fire and stay there forever [Rev. 20:11-15].
Jehovah Witnesses believe that in paradise the righteous will have eternal life on earth, and the unrighteous will be annihilated. They do not believe in a literal hell with conscious punishment forever. They do not believe this present earth will be destroyed, but become a peaceful paradise. This is contrary to what the Holy Scriptures teach [Rev. 20:10-15]. Note v. 10 says “day and night forever.” Also, this present earth is not paradise [Rev. 21:1, 5]. Noticed this present earth passes away, and He makes all things new. This takes place after the Great White Throne judgment of the wicked. In fact, we are told how it happens, it shall be destroyed by fire [2 Peter 3:10-13].