(a) Umm Farwah (may Allah be pleased with her) said that the Messenger of Allah (peace and blessings be upon him) was asked which deeds are best. He (peace and blessings be upon him) said: "Performing the prayer at the beginning of its time."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1100