Ibn Abbas radiyallahu anhu reports, “Khalid ibn Waleed and I both accompanied Rasoolullah sallallahu alaihe wasallam to the house of Maymunah. (Ummul Mu’mineen, Maymunah radiyallahu anha was the maternal aunt of both). She served milk in a vessel. Rasoolullah sallallahu alaihe wasallam drank from it. I was on his right and Khalid ibn Waleed on his left. Rasoolullah sallallahu alaihe wasallam said the right of drinking is now yours (as you are on the right). If you so wish you could give your right to Khalid. I replied that I would give no one preference from your left over. After that Rasoolullah sallallahu alaihe wasallam said, Whenever Allah feeds one something, this du’aa should be recited:
Allahumma baarik lanaa fihi wa-at’imanaa khayram minhu
(Translation: O’ Allah grant us barakah in it, and feed us something better than it.)
Whenever Allah gives someone milk to drink one should read:
Allahumma baarik lanaa fihi wa-zidnaa minhu
(Translation: O’ Allah grant us barakah in it and increase it for us.)
Sayyidinaa Ibn Abbas radiyallahu anhu says that after having something Rasoolullah sallallahu alaihe wasallam made du’aa for something better than it. And after drinking milk he taught to make du’aa for the increase of it, becuase Rasoolullah sallallahu alaihe wasallam said, There is nothing that serves both as food and water excepting milk.”