Abu Ubaydah narrates that it weighed very heavily upon Abdullah bin Mas'ud (may Allah be pleased with him) that he should not remember Allah and recite the Qur'an until he had performed the Fajr prayer.
(b) It has been narrated to us concerning Sa'id bin Jubayr and Ibrahim bin Yazid al-Nakha'i (may Allah have mercy on them both) that both of them disliked talking after the two rak'ahs of Fajr, and perhaps they disliked idle, pointless speech.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3034