Sayyiduna Uqbah bin Amir (may Allah be pleased with him) said that the Prophet (peace and blessings be upon him) said: "There is no rider who, being alone on his journey, occupies himself with the remembrance of Allah, except that an angel rides behind him; and whoever occupies himself with poetry and the like, a devil rides behind him."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 14966