Sayyiduna Abdullah bin al-Sa'di (may Allah be pleased with him), who belonged to the tribe of Malik bin Hisl, says: I came to the Noble Messenger (peace and blessings be upon him) with a few of my companions. When they dismounted from their riding animals, they said: You guard the mounts; when we have fulfilled our need, you go to the Noble Messenger (peace and blessings be upon him) and fulfil your need. And I was the youngest. When they came back having fulfilled their need, they said to me: Now you go. He says: When I went to the Noble Messenger (peace and blessings be upon him), he (peace and blessings be upon him) said: "What is your need?" I said: My need and request is that you tell me about emigration: has emigration come to an end? He (peace and blessings be upon him) said: "Your need is among the best of their needs. Emigration will not come to an end as long as the enemy is being fought."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 17779