And from ‘Aaishah radi Allaahu ‘anhaa that the Prophet sall Allaahu ‘alaihi wa sallam said:

“Seek out laylat ul qadr in the odd nights from the last ten.”

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The Shaykh Muhammad ibn Saalih al ‘Uthaymeen rahimahullaah commented:

In the odd nights from the last ten
– this is the night of the 21st and the 23rd and the 25th and the 27th and the 29th

The Mother of the Believers ‘Aaishah radi Allaahu ‘anhaa informed that the Prophet sall Allaahu ‘alaihi wa sallam directed (us) to seek to encounter laylat ul qadr with righteous deeds and standing (in prayer) in it during the odd nights of the last ten of Ramadaan.

(taken from Sh Uthaymeen’s explanation of ‘Umdat-ul-Ahkaam
translated by Nasser ibn Najam)