Shaddad bin Ma'qil said that Sayyiduna Abdullah (may Allah be pleased with him) said: "The first thing of your religion that you will lose is trustworthiness (amanah), and the last thing to remain will be the prayer; and there will be people who pray while they have no religion."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 9528