The key to prayer is ṭahārah (purity/cleanliness) because any impurities mean than you cannot pray. The Messenger of Allāh’s (May Allāh praise him and Peace be upon him) said, “Purity/cleanliness is the key to prayer.” [Authenticated by Sheikh Al Albānī in Ṣaḥīḥ Al-Jāmi` 5885]