Narrated Jabir bin 'Abdullah (RA): A person entered the masjid while the Prophet (ﷺ) was delivering the Khutba on a Friday. The Prophet (ﷺ) said to him, "Have you prayed?" The man replied in the negative. The Prophet (ﷺ) said, "Get up and pray two Rakat." [Sahih Bukhari]
Meaning: It is of great importance to always perform two Rakat upon entering the mosque before sitting down or doing anything in as much as we are purified.
In respect to today been Jumuah day, do not forget to recite Suratul Kahf.
