Ibn 'Abbas said, "'Umar asked permission to visit the Prophet, may Allah bless him and grant him peace, and said, 'Peace be upon the Messenger of Allah! Peace be upon you! Can I come in?'"  

عَنِ ابْنِ عَبَّاسٍ قَالَ اسْتَأْذَنَ عُمَرُ عَلَى النَّبِيِّ ﷺ فَقَالَ السَّلاَمُ عَلَى رَسُولِ اللهِ السَّلاَمُ عَلَيْكُمْ أَيَدْخُلُ عُمَرُ؟