Fiqh-us-Sunnah Volume 4, Funerals and Dhikr, Fiqh 4.111A.

Section : Supplicating at the most Opportune Times and Locations..

These are, for instance, the day of ‘Arafah, month of Ramadan, Friday, the last part of the night, at dawn, during prostration, at the time of rainfall, between the azhan and iqamah, at the time of encounter of armies, at times of panic, and when one’s heart is soft and tender.

Abu Umamah reported, “The Prophet, peace be upon him, was asked, ‘What supplication finds the greatest acceptance?’ He answered: ‘A prayer offered in the middle of the latter part of the night and after the prescribed Prayers’.’ (Reported by Tirmizhi with a sound chain of authorities)

Abu Hurairah reported, the Prophet, peace be upon him, said, “The servant is nearest to his Lord when he is prostrating to Him, so make supplication in this state.” (Muslim) There are very many hadith found in various books on this subject.