Laylatul Qadr is the Night of Decree. It is one of the last ten nights of Ramadan. The last ten nights begin from the sunset of the 20th day of Ramadan. So, if today is the 20th and the sunset or the Maghrib is an hour from now, once the sun sets, this begins the last ten nights of Ramadan. And the most favored night of these ten is the 27th. (But it is not a must that Laylatul Qadr will be on the 27th, as most Muslims believe). Also, it is most likely to be on the odd nights; that is, the nights of the 21st, the 23rd, the 25th, the 27th and the 29th of Ramadan.
This night, as Allah has described in the Quran in a Surah named after it, is better than a thousand months.

قَالَ تَعَالَى : {لَيْلَةُ القَدْرِ خَيْرٌ مِنْ ألْفِ شَهْرٍ} القدر : ٣

Allah said: “The Night of Decree is better than a thousand months.”
{Surat Al-Qadr : 3}

This one particular night is better and more important than a thousand months. Scholars differed in their explanations about this; one of these is that, since Allah gave long lives to previous nations, they could do a lot more good deeds than us. So, Allah gave us this night so we could get as many rewards as them. For example, the Jews came around 3000 years before us, and they lived long lives; the people’s lives would be 200, maybe 300 years. Which means that they could fill them up with forms of worship far more than the 60 or 70 years that we live on Earth. Another example is of Nuh, peace be upon him, who lived for 950 years, and some say he lived longer (he gave Da’wah for 950 years but lived longer than that). So, they had long lives and the ability to fill them up with good deeds.
Our lifespan is short, so Allah is compensating us by giving us one night in a year, that is equivalent to 83 plus years of good deeds. If we succeed in worshipping Allah in this night, (which is only a few hours; about 8 – 10 hours), this would be better than worshipping Allah in 83 years or more. So, this is a glorious night.

The Prophet ﷺ used to do an excellent thing during the last ten nights of Ramadan, and that is, pray all night long.
Whenever the last ten nights of Ramadan entered, the Prophet ﷺ firstly used to tighten his waist wrapper {some scholars say that this is a metaphor for not having any intimacy with his wives. Others say that it is a metaphor for trying to do his level best in forms of worship}. Secondly, he used to wake up his wives for worship. Thirdly, he used to make the whole night alive with night prayers, praying long Rak’ahs and reciting the Quran during these last ten nights.
So, these are the deeds that we are recommended to do in the last ten nights of Ramadan.
Most of us will not be able to do even half of that. So, you do whatever you can to the best of your ability. Engage in making Du’aa because Mother ‘Aishah, may Allah be pleased with her, once came to the Prophet ﷺ and said, “O Prophet of Allah, teach me something to say if I were to notice Laylatul Qadr.” So, the Prophet ﷺ said to her, “Say:

اللَّهُمَّ إِنَّكَ عَفُوٌّ تُحِبُّ الْعَفْوَ فَاعْفُ عَنِّي

‘O Allah, you are Pardoning and you love to pardon, so pardon me.’”

If you pray a little bit, make Du’aa for a while, recite the Quran a little bit, do Zikr a little bit, so that the whole night is engaged in doing good deeds, that would be an excellent thing for you to do.

What is Laylatul Qadr? What are the acts that we are encouraged to do in this night?