He the Holy Prophet Muhammad (saw) said, "On the night of Isra and Miraj (Shab-E-Meraj) when I ascended to the heavens, I saw an Angel who had a thousand hands. On each of his hands there were a thousand fingers, and he was counting something on them.
I asked Jibreel (pbuh) as to who that Angel was, and what was he counting? Jibreel (pbuh) replied that the Angel had been appointed by Allah to count the drops of rain, so that it may be known as to how many drops have fallen down to the earth.
I turned towards the Angel and asked him, "Do you know the total amount of the raindrops which have fallen down on the earth from the day Allah created this world till now"? To which he replied, "O Prophet of Allah! I swear by my Lord who has chosen you (as a blessing) for mankind, verily I know the total amount of raindrops fallen on the earth till now. Even to the extent that how many drops have fallen in the wilds, in the prosperous lands, in the gardens, and also in the cemetery." Then I told him that I was very much surprised by the power of his mind and intellect and the ability to remember, to which he replied, "O Prophet of Allah! Verily this ability to count proves futile when I try to count only one thing." I asked him as to what calculation was that. He replied, "When people of your Ummah gather at one place and send Salawat (Salat and salam) upon you, it is beyond my ability and capacity to count the rewards for it."