The Door to Eternal Paradise

God has said in the Quran:
"And give good news (O Muhammad) to those who believe and do good deeds, that they will have gardens (Paradise) in which rivers flow...."(Quran, 2:25)

God has also said:
"Race one with another for forgiveness from your Lord and for Paradise, whose width is as the width of the heavens and the earth, which has been prepared for those who believe in God and His messengers...."(Quran, 57:21)

The Prophet Muhammad told us that the lowest in rank among the dwellers of Paradise will have ten times the like of this world, and he or she will have whatever he or she desires and ten times like it.
Also, the Prophet Muhammad said:
{A space in Paradise equivalent to the size of a foot would be better than the world and what is in it.}
Narrated in Saheeh Al-Bukhari, and Mosnad Ahmad

He also said:
{In Paradise there are things which no eye has seen, no ear has heard, and no human mind has thought of.}
Narrated in Saheeh Muslim, and Mosnad Ahmad

He also said:
{The most miserable man in the world of those meant for Paradise will be dipped once in Paradise. Then he will be asked, “Son of Adam, did you ever face any misery? Did you ever experience any hardship?” So he will say, “No, by God, O Lord! I never faced any misery, and I never experienced any hardship.”}
Narrated in Saheeh Muslim, and Mosnad Ahmad

If you enter Paradise, you will live a very happy life without sickness, pain, sadness, or death; God will be pleased with you; and you will live there forever.
God has said in the Quran:
"But those who believe and do good deeds, We will admit them to gardens (Paradise) in which rivers flow, lasting in them forever...."(Quran, 4:57)

Source:
A Brief Illustrated Guide to Understanding Islam