Humble Supplication - Section 2 Mishkat al-Masabih 1291
Arabic hadith text
وَعَنْ أَنَسٍ: أَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَنَتَ شَهْرًا ثُمَّ تَرَكَهُ. رَوَاهُ أَبُو دَاوُد وَالنَّسَائِيّ
Translation
Anas said that the Prophet stood in humble supplication for a month and then gave it up. Abu Dawud and Nasa'i transmitted it.