Is there a hadith for that? Besides, didn't Muhammad say that he didn't know when the day of judgment would be?
Some hadith:
Sahih Muslim, Book 41, Number 7050:
'A'isha reported that when the desert Arabs came to Allah's Messenger (may peace be upon him) they asked about the Last Hour as to when that would come. And he looked towards the youngest amongst them and said: If he lives he would not grow very old that he would find your Last Hour coming to you he would see you dying.
Sahih Muslim, Book 41, Number 7051:
Anas reported that a person asked Allah's Messenger (may peace be upon him) as to when the Last Hour would come. He had in his presence a young boy of the Ansar who was called Mahammad. Allah's Messenger (may peace be upon him) said: If this young boy lives, he may not grow very old till (he would see) the Last Hour coming to you.
Sahih Muslim, Book 41, Number 7052:
Anas b. Malik reported that a person asked Allah's Apostle (may peace be upon him): When would the Last Hour come? Thereupon Allah's Messenger (may peace be upon him) kept quiet for a while, then looked at a young boy in his presence belonging to the tribe of Azd Shanilwa and he said: If this boy lives he would not grow very old till the Last Hour would come to you. Anas said that this young boy was of our age during those days.
Sahih Muslim, Book 41, Number 7053:
Anas reported: A young boy of Mughira b. Shu'ba happened to pass by (the Holy Prophet) and he was of my age. Thereupon Allah's Apostle (may peace be apon him) said: If he lives long he would not grow very old till the Last Hour would come (to the old People of this generation).
Sahih al-Bukhari, Volume 1, Book 3, Number 116:
Narrated 'Abdullah bin 'Umar:
Once the Prophet led us in the 'Isha' prayer during the last days of his life and after finishing it (the prayer) (with Taslim) he said: "Do you realize (the importance of) this night? Nobody present on the surface of the earth tonight will be living after the completion of one hundred years from this night."
Sahih al-Bukhari, Volume 1, Book 10, Number 539:
Narrated Abdullah:
"One night Allah's Apostle led us in the 'Isha' prayer and that is the one called Al-'Atma by the people. After the completion of the prayer, he faced us and said, ‘Do you know the importance of this night? Nobody present on the surface of the earth tonight will be living after one hundred years from this night.’" (See Hadith No. 575).
Sahih al-Bukhari, Volume 1, Book 10, Number 575:
Narrated 'Abdullah bin 'Umar:
The Prophet prayed one of the 'lsha' prayer in his last days and after finishing it with Taslim, he stood up and said, "Do you realize (the importance of) this night? Nobody present on the surface of the earth tonight would be living after the completion of one hundred years from this night."