It is narrated from Sayyiduna Abu Umamah (may Allah be pleased with him) — or from his brother — that the Prophet (peace and blessings be upon him) said: "Do not pray when the sun is rising, for it rises between the two horns of Satan, and every disbeliever prostrates to it; nor when the sun is setting, for it sets between the two horns of Satan, and every disbeliever prostrates to it; nor at midday, for at that time Hell is stoked."
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 8075