Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) narrated: On the day of Badr they were made to appear very few in our eyes, so much so that I said to my companion who was beside me: How many do you think they are? Do you think they are seventy? He said: I think they are a hundred. Then we captured a man from among them and asked him, and he said: We were a thousand.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 10231