SHAFAQNA – Imam Sadeq (AS) narrated from the Prophet of Islam (PBUH) who said: Whoever performs the Fajr (Dawn) Salaat and Isha (Night) Salaat in congregation, will be under the protection of Allah (SWT), and if he/she is oppressed by another person, is like God has been oppressed and if he/she is scorned is like God has been scorned .
The Prophet (PBUH) also said: If people knew the rewards for performing Fajr and Isha Salaats in congregation, will come towards them, even on their hands and knees . In another narration, the Prophet (PBUH) said: Whoever performs Fajr (Dawn) and Isha (Night) congregational prayers in Mosque is like he/she has kept a vigil the whole night (for performing prayers) .
One day, after the end of the Fajr congregational prayers in the Mosque, the Prophet (PBUH) faced people and asked about those who were absent one by one and wanted to know if they were present in the prayers? The companions replied: No, they are not present. The Prophet (PBUH) asked: Are they absent? Then the Prophet [PBUH] said: Verily, no other prayers are more difficult for the hypocrites than Fajr and Isha Salaats .
 Almahasen, Vol. 1, Page 52.
 Manla Yahzarahul Faqih, Vol. 1, Page 377.
 Wasa’elul Shia, Vol. 8, Page 295.
 Almahasen, Vol. 1, Page 84.