once, passing through a desert, Rasool Allah (P.B.U.H) and his companions happened to come across a person tending camels and requested him to provide them with some milk. The man excused himself saying: "The milk that is in the breasts of these camels is for the breakfast of the people of the tribe and that, which lies in the container, is for their evening meals."
When he heard this, Rasool Allah (P.B.U.H) prayed for him, saying: "O' Lord! Increase this person in wealth and children" - and the group continued on its way. A little later they came across another person, who too was engaged in feeding the camels. When they requested him to provide them with some milk, he immediately milked the she-camels and poured all of the milk in the vessels of Rasool Allah (P.B.U.H). In addition to the milk he even presented them with a sheep and said: At the moment this is all I can offer but if you desire I shall arrange for more.
Rasool Allah (P.B.U.H) raised his holy hands and prayed: "O' Lord! Grant him sustenance in a measure that is sufficient for him."
Astonished, his (P.B.U.H) companions said: "O' Prophet of Allah! For the person who rejected your request you sought something which all of us long for, whereas for the one who fulfilled your desire, you prayed for something, which none of us prefer (sustenance in a measure that is just sufficient and not excess)!"
Rasool Allah (P.B.U.H) said: "A livelihood that is less but sufficient for (fulfilling the needs of) one's life is better than great riches that engross man in itself." He (P.B.U.H) then supplicated: "O' Lord! Grant Muhammad and his Progeny a sustenance in the measure that is just sufficient (for them).
source : sibtayn
