It is narrated from Sayyidah Aishah (may Allah be pleased with her) that she used to say: "How strange is the Muslim man who, when he enters the Ka'bah, raises his gaze toward the ceiling, whereas he should refrain from that out of reverence and veneration for Allah. When the Messenger of Allah (peace and blessings be upon him) entered the Ka'bah, his gaze did not go beyond the place of his prostration until he came out of it." This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it!