The following are excerpts from a lecture by Saudi cleric 'Aed Al-Qarni:
Al-Qarni: The Prophet Muhammad, as is said in the Hadith, sent Ali to the Jews A– to the Jews, the brothers of apes and pigs, to fight them. Ali, being so brave and daring, thought he was sent to behead them. The Prophet Muhammad told him that it was better to guide them to the righteous path than to kill them and that the goal of the mission was to draw the Jews to the religion of Islam so they would convert, and increase the number of Muslims. Guiding them to heaven is better than slaughtering them.
By Allah, if you guide a Jew or a Christian to the righteous path it is better than slaughtering one or two thousand of them on the battlefield.