Sayyiduna ‘Umar (radiyallahu’anhu) reports that Rasulullah (sallallahu’alayhi wasallam) said:

‘Anyone who recites the following after wudu, will have all eight doors of Jannah opened for him to enter from whichever of them he wishes:

Ash-hadu al la ilaha illallahu wahdahu la sharika lahu wa ash-hadu anna Muhammadan ‘Abduhu wa Rasuluh

(I bear witness that no-one is worthy of worship but Allah, the One alone, without partner, and I bear witness that Muhammad is His servant and Messenger)

(Sahih Muslim, Hadith: 552)