He had been treated kindly by Muhammad after the Battle of Badr, being a poor man with daughters, he had no means to pay ransom, he was released after Battle of Badr, on the condition that he would not take up arms against Muslims again.
He pleaded for mercy again, but Muhammad ordered him to be killed.
[1] He was an influential poet who used his poetry to mobilize the masses against Muhammad.
During the Battle of Uhud he used his poetry again to mobilise the masses against Muhammad.
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