It is narrated from Sayyiduna Abu Umamah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "That I remember Allah from the break of dawn until sunrise, saying takbir, tahlil and tasbih, is dearer to me than freeing four slaves from the descendants of Isma'il (peace be upon him); and that I remember Allah from after the Asr prayer until sunset is dearer to me than freeing such-and-such a number of slaves from the descendants of Isma'il (peace be upon him)."
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 7997