Sayyiduna Abu Hurairah (may Allah be pleased with him) narrated from the Messenger of Allah (peace and blessings be upon him), he (peace be upon him) said: "Whoever brings a good deed will have a reward better than it, and they (the righteous) will be safe from the terror of that Day." He said: That (good deed) is «لا الهٰ الا الله» , and whoever brings an evil (sin), their faces will be thrown down into Hellfire. He said: "That (sin) is shirk (associating partners with Allah)."