The Messenger of Allah ﷺ used to say in his prayer, "O Allah, I ask You for firmness in all matters and resolve in following right guidance. I ask You to enable me to give thanks for Your blessings and to worship You well. I ask You for a sound heart and a truthful tongue. I ask You for the best of what You know, I seek refuge in You from the evil of what You know, and I seek Your forgiveness for what You know."
أخبرنا أبو داود قال حدثنا سليمان بن حرب قال حدثنا حماد بن سلمة عن سعيد الجريري عن أبي العلاء
أن رسول الله ﷺ كان يقول في صلاته اللهم إني أسألك الثبات في الأمر والعزيمة على الرشد وأسألك شكر نعمتك وحسن عبادتك وأسألك قلبا سليما ولسانا صادقا وأسألك من خير ما تعلم وأعوذ بك من شر ما تعلم وأستغفرك لما تعلم
[Hasan] Reported by Ibn Hibban (Mawarid), no. 2416, from the hadith of Hammad bin Salama, with this wording, and it is in al-Kubra, no. 1227.Abu Ala bin Shakhir heard it from a man of Banu Hanzala, Shaddad, with this wording, as in Sunan Tirmidhi, no. 3407, and elsewhere. The hadith has corroborating narrations in Tabarani (al-Kabir 7/279, no. 7135) and elsewhere.