Hadhrat Bareedah (Allah be pleased with him) narrates that Muhammad (peace be upon him) said: “The subject of pledge which exists between the people and us (the Ambiyaa) is Salaat. Thus, whoever neglects Salaat has become a kaafir (i.e. in terms of practical life, not in terms of Imaan).” (Ahmad, Tirmidhi, Nisai, Ibn Majah).