Sayyiduna Abu Umamah Radiyallahu anhu narrates
that indeed Rasullullah Sallallahu alaihi wasallam said:
My sitting after Salat-ul-Fajr,
in remembering Allah Subhanahu wa ta'ala,
by extolling Him, praising Him, glorifying Him,
and testifying His oneness
( La Illaha Illah Allah )
untill the sun rises,
is dearer to me than the freeing of two or more slaves from amongst
the descendents of Ismail Alaihissalam.
And, similary, after Sala-tul-Asr until the setting of the sun,
(engagement of deeds mentioned above)
is dearer to me than the freeing of four slaves from amongst
the descendents of Ismail Alaihissalam.
{ Musnad Ahmad }