Majma al-Zawaid — Hadith 5747

Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) says: I do not like to pray inside the Ka'bah, because whoever prays inside the Ka'bah will have part of it behind his back. My brother told me that when the Prophet (peace and blessings be upon him) entered it, he went down into prostration between the two pillars, then he sat and continued supplicating; he did not pray (inside the Ka'bah).
Al-Tabarani recorded it in al-Mu'jam al-Kabir; its chain contains Ibn Ishaq, who is thiqah (trustworthy) but a mudallis (one who commits tadlis).