It is narrated from Sayyiduna Shaddad bin Aws (may Allah be pleased with him) that the Prophet of Allah (peace and blessings be upon him) used to say in his prayer: "O Allah, I ask You for steadfastness in the matter (of religion) and firm resolve upon right guidance; I ask You for gratitude for Your blessing and excellence in Your worship; I ask You for a sound heart and a truthful tongue; I ask You for the good that You know, I seek refuge in You from the evil that You know, and I seek Your forgiveness for what You know."
Hadith Referenceالمعجم الكبير للطبراني / باب الشين / 7148