Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "These five prayers are true, and they are an expiation for the sins committed between them, as long as major sins are avoided."
Al-Bazzar recorded it, and al-Tabarani in al-Mu'jam al-Kabir. Its chain contains a narrator, Salih bin Musa, who is munkar al-hadith (his narrations are rejected).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصلاة / 1656