Is it permissible to supplicate with the phrase: "O Lord, grant me a strong heart to bear my own mistakes, and a stronger heart to bear the mistakes of others, and a believing heart to cast all these worries upon You"?

It is best for a Muslim to choose the ma’thur supplications (those transmitted from the Prophet) and the comprehensive supplications that are authentically established from the Messenger of Allah, peace and blessings be upon him. Authentic hadiths have been narrated recommending some of these supplications, such as the saying of Aishah, may Allah be pleased with her: "O Aishah, adhere to the comprehensive and complete supplications. Say: 'O Allah, I ask You for all good, hastened and delayed, that which I know and that which I do not know. And I seek refuge in You from all evil, hastened and delayed, that which I know and that which I do not know. O Allah, I ask You for Paradise and what brings one closer to it of word or deed, and I seek refuge in You from Hellfire and what brings one closer to it of word or deed. O Allah, I ask You for what Muhammad, peace and blessings be upon him, asked You for, and I seek refuge in You from what Muhammad, peace and blessings be upon him, sought refuge in You from. O Allah, whatever decree You have decreed for me, make its outcome guidance for me.'" Also, "the supplication of Dhun-Noon (Jonah) when he was in the belly of the whale: 'There is no god but You; glory be to You! Indeed, I was among the wrongdoers.'" And, "O Allah, I ask You, by virtue of the fact that all praise is due to You, there is no god but You, the Bestower, the Originator of the heavens and the earth, O Possessor of majesty and honor, O Ever-Living, O Sustainer, I ask You."

Nevertheless, it is permissible for a Muslim to supplicate with whatever supplications he can formulate himself, as long as his supplication does not involve sin, severing ties of kinship, polytheism (shirk), or bad manners. It is desirable to precede the supplication with praise of Allah. There is no harm in complaining of worry and grief to Allah, as Yaqub (Jacob), peace be upon him, did.