It is narrated from Hazrat Samurah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "Kill the elderly among the polytheists and leave their young alive." Benefit: The son of Imam Ahmad says that I asked my father for clarification of this hadith, so he said that an old man generally does not accept Islam, whereas a young man does; thus, a young person is closer to Islam compared to an old man.
Hadith Referenceمسند احمد / أول مسند البصريين / 20230
Hadith Gradingحکم دارالسلام:إسناده ضعيف، الحسن البصري مدلس، وقد عنعن