Narrated Aamir bin Saad (raa): that his father said, "In the year of Hajjatal-Wada’, the Prophet (saws) paid me a visit while I was suffering from an ailment that had brought me to the verge of death.
I said, ‘O Allah’s Apostle! My sickness has reduced me to the (bad) state as you see, and I am a rich man, but have no heirs except one daughter. Shall I give 2/3 of my property in charity?’
He said, ‘No.’ I said, ‘Then 1/2 of it?’
He said, ‘Even 1/3 is too much, for, to leave your inheritors wealthy is better than to leave them in poverty, begging from people. And (know that) whatever you spend in Allah’s Cause, you will get reward for it, even for the morsel of food which you put in your wife’s mouth.’
I said, ‘O Allah’s Apostle! Will I be left behind my companions (in Mecca)?’
He said, ‘If you remain behind, whatever good deed you will do for Allah’s Sake, will raise and upgrade you to a higher position (in Allah’s Sight). May be you will live longer so that some people may benefit by you, and some others (pagans) may get harmed by you.
O Allah! Complete the migration of my companions and do not turn them on their heels; But (we pity) the poor Saad bin Khaula (raa) (not the above mentioned Saad) (died in Mecca)" Allah’s Apostle lamented (or pitied) for him as he died in Mecca.
Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi): Volume 5, Book 59, Number 693
Innvocations: Volume 8, Book 75, Number 384