Prophet Muhammad (pbuh) said, "He who observes Al-Bardan (i.e., Fajr and `Asr prayers) will enter Jannah.Sahih Bukhari and Muslim, Narrated by Abu Musa. In another hadith: Muhammad said 'He who misses his Asr Salah (i.e. reads it after its specified time) is as if he has lost his wife, children and all his wealth.’ (Sahih Muslim)
Goes w/o saying all 5 sawlah are important, as is 'Asr :) . Narrated Ibn 'Umar: Allah's Apostle (peace be upon him) said, "Whoever misses the 'Asr prayer (intentionally) then it is as if he lost his family and property." (Saheeh Al Bukhari, Book Hadith
Narrated Ibn Abu Malih: I was with Buraida on a cloudy day and he said, “Offer the `Asr prayer earlier as the Prophet (PBUH) said, ‘Whoever leaves the `Asr prayer will have all his (good) deeds annulled.” Sahih al-Bukhari Vol.