Allah called His Messenger an `Abd (servant) when He mentioned sending down His Book, the Prophet's involvement in inviting to Him, and when mentioning the Isra' (overnight journey from Makkah to Jerusalem and then to heaven), and these are the Prophet's most honorable missions. Allah said,
﴿الْحَمْدُ لِلَّهِ الَّذِى أَنْزَلَ عَلَى عَبْدِهِ الْكِتَـبَ﴾
(All praise and thanks be to Allah, Who has sent down to His servant (Muhammad ) the Book (the Qur'an)) (18:1),
﴿وَأَنَّهُ لَّمَا قَامَ عَبْدُ اللَّهِ يَدْعُوهُ﴾
(And when the servant of Allah (Muhammad ) stood up invoking Him (his Lord ـ Allah in prayer)), (72:19) and,
﴿سُبْحَانَ الَّذِى أَسْرَى بِعَبْدِهِ لَيْلاً﴾
(Glorified (and Exalted) be He (Allah) (above all that they associate with Him) Who took His servant (Muhammad ) for a journey by night) (17:1).