Al-e-Imran (The House of Imran) - Chapter 3: Verse 195 (partial)
"... a reward from the presence of Allah and from His presence is the best of rewards."
The word thaba, yathubu, thawban originally means to return and to come back and one of its derivatives is thawab that signifies the fruit or the result of one's work or efforts, good or bad depending on the nature and quality of one's action. However, it is mostly used in a good sense, as something good gained in consequence of a good deed.
By describing the enduring rewards and gifts to be granted by Allah to His servants for their small and insignificant deeds as thawab, our Sustainer Most Gracious has immensely enhanced the importance of human deeds. Otherwise, there is hardly any comparison between the abiding reward in the hereafter and trifling human deeds in this worldly life, just as it is impossible to compare a miniscule speck of dust to the mighty Himalayas. It is this wide gap between the deeds of humans and their enduring reward from Allah that the words "from the presence of Allah, and from His presence is the best of rewards" seek so beautifully to bridge. It is like saying in fact that though this is a reward for your efforts and works, it is from Allah Who has infinite treasures of the best of rewards. He is Most Generous and He blesses whomsoever He wishes with whatever and howsoever He wills.
"Pondering Over The Qur'an: Surah Ali Imran" - Amin Ahsan Islahi