The Messenger (peace and blessings be upon him) said: "If you had said 'Bismillah', the angels would have carried you away while the people were watching." The Prophet (peace and blessings be upon him) said this to Sayyiduna Talhah (may Allah be pleased with him) when he said "Oh!" due to some pain. This hadith is also narrated mursal from Sayyiduna Jabir, Sayyiduna Anas (may Allah be pleased with them both), and Ibn Shihab.