Musannaf Ibn Abi Shaybah

The son of Hazrat Abdullah bin Salam (may Allah be pleased with him) narrates that once, when I was preparing to set out for jihad, my father said to me: "Wait, O my son!" I said, "Could you not have stopped me earlier, before I had made preparations and spent money on it?" He replied, "I wanted that the reward of a mujahid be written for you." Pointing towards Syria, he said, "A calamity is about to come from that direction. If I live to see it, you will see what I do in it, and if I do not live to see it, then you should rush towards it eagerly."