The Prophet Muhammad (SAW) taught this following du’a (supplication) to his wife Aisha for Lailatul Qadr.
A night such as Lailatul Qadar was not granted to any ummah (religious community) before the Muslims. Only the ummah of the Prophet Muhammad (SAW) were favoured with a night of huge reward. One reason this was granted was to enable Muslims to equal the worship of the people who lived before this ummah. In the distant past, it is said that people lived very long lives of hundreds of years.
Today, we live with much shorter lifespans. And so, Allah SWT gave us Lailatul Qadr to enable us to do as much worship as a man who lived even hundreds of years longer. If in a lifetime, one was able to only worship on Lailatul Qadr ten times, he would have equaled in those ten nights, 833 years of worship.