Jami` at-Tirmidhi Book 48, Hadith 210
`Amr bin `Abasah reported to me that he heard the Prophet (ﷺ) say: “The closest that the Lord is to a worshipper is during the last part of the night, so if you are able to be of those who remember Allah in that hour, then do so.”
“Supplicate to Allah to heal me.” He (ﷺ) said: “If you wish I will supplicate for you, and if you wish, you can be patient, for that is better for you.” He said: “Then supplicate to Him.” He said: “So he ordered him to perform Wudu’ and to make his Wudu’ complete, and to supplicate with this supplication: ‘O Allah, I ask You and turn towards You by Your Prophet Muhammad (ﷺ), the Prophet of Mercy. Indeed, I have turned to my Lord, by means of You, concerning this need of mine, so that it can be resolved, so O Allah so accept his intercession for me (Allāhumma innī as’aluka wa atawajjahu ilaika binabiyyka Muḥammadin nabi-ir-raḥmati, innī tawajjahtu bika ila rabbī fī ḥājatī hādhihī lituqḍā lī, Allāhumma fashaffi`hu fīyya).’”
“I heard the Messenger of Allah (ﷺ) saying; ‘Indeed, Allah, the Mighty and Sublime, says: “Indeed My worshipper who is entirely My slave is the one who remembers Me when he is about to meet his enemy.” That is: “At the time of fighting.”