Praying Fajr and Isha Prayers

Abu Hurayra reported that the Messenger of Allah, (may Allah bless him and grant him peace) said, 

"And if they only knew what was in the prayers of 'Isha' and Subh [Fajr], they would come to them even if they had to crawl."

[Al-Bukhari & Muslim]

`Uthman bin `Affan (May Allah be pleased with him) reported: I heard the Messenger of Allah (may Allah bless him and grant him peace) saying, 

"One who performs `Isha' prayer in congregation, is as if he has performed Salat for half of the night. And one who performs the Fajr prayer in congregation, is as if he has performed Salat the whole night.''

[Muslim]

Abu Hurairah (May Allah be pleased with him) reported: The Messenger of Allah (may Allah bless him and grant him peace) said, 

"No Salat is more burdensome to the hypocrites than the Fajr (dawn) prayer and the `Isha' (night) prayer; and if they knew their merits, they would come to them even if they had to crawl to do so.''

[Al-Bukhari & Muslim]