The Prophet Muhammad (peace be upon him) dispatched towards the sea-shore an expedition of three hundred men, under the command of Abu Ubaidah (ra) in 8 A.H. He gave them a bag full of dates for their rations. They had been hardly out for fifteen days when they ran short of rations. In order to provide the contingent with food, Qais (ra) began buying three camels daily from his own men, to feed the Mujahideen, with a promise to pay on return to Madinah. The Amir seeing that the slaugther of camels would deprive the party of their only means of transport, prohibited him to do so. He collected the dates that had been left with each person and stored them in a bag. He would issue one date to each man as his daily ration. When Jabir (ra) later on narrated this story to the people, one of his audience inquired:
"How did you manage to live upon one date only for the whole day?" He replied: "We longed even for that one date, when the whole stock was exhausted. We were on the verge of starvation. We moistened the dry tree-leaves with water and ate them."
When they reached this stage, Allah had mercy on them for He always brings ease after every hardship, provided it is endured patiently. A big fish known as "Ambar" was thrown out of the sea for them. The fish was so big that they lived on it for eighteen days altogether. They also filled their satchels with the remaining portion, which lasted them right up to Madinah. When the episode was narrated to the Prophet (peace be upon him), he said: "The fish was a provision arranged for you by Allah."
Source: From the book "Stories of the Sahabah" by Shaikh Muhammad Zakariyya Kandhalvi.
We are Muslims today because of such sacrifices by the companions of Prophet Muhammad (peace be upon him). We should remember these events as a source of comfort whenever we too are faced with difficulties regarding practising Islam.