'Abdullah bin Mas'ud narrated "The Messenger of Allah (s.a.w) drew a square line (on the ground) forus, and in the middle of the (square) line he drew another line, and he drew another line going out of the (square) line.Around the one that was in the middle, he drew (various) lines. Then he said:
'This is the son of Adam, and this is his life-span encircling him, and this one in the middle in the person, and these lines are his obstacles, if he escapes this one, this one ensnares him, and the line extending outside is his hope.'"
English reference: Vol. 4, Book 11, Hadith 2454
Arabic reference: Book 37, Hadith 2642