It is narrated from Hazrat Hudhaifa (may Allah be pleased with him) that once I stood in prayer at night with the Noble Prophet (peace and blessings be upon him). The Noble Prophet (peace and blessings be upon him) recited seven long surahs in seven rak'ahs, and after raising his head from bowing, he would say "Sami' Allahu liman hamidah," then say, "Alhamdulillah dhi al-malkut wal-jabarut wal-kibriya' wal-'azamah." And his bowing was as long as his standing, and his prostration was as long as his bowing. When the prayer was finished, my legs were close to breaking.