Yahya related to me from Malik that Sumayy, the mawla of Abu Bakr ibn Abd ar-Rahman, heard Abu Bakribn Abd ar-Rahman say, "A woman came to the Messenger of Allah, may Allah bless him and grant him peace, and said, 'I had arranged to do hajj, but I was prevented,' and the Messenger of Allah, may Allah bless him and grant him peace, said, 'Do umra in Ramadan, for doing umra in it is like doing hajj.' "


وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ سُمَىٍّ، مَوْلَى أَبِي بَكْرِ بْنِ عَبْدِ الرَّحْمَنِ أَنَّهُ سَمِعَ أَبَا بَكْرِ بْنَ عَبْدِ الرَّحْمَنِ، يَقُولُ جَاءَتِ امْرَأَةٌ إِلَى رَسُولِ اللَّهِ صلى الله عليه وسلم فَقَالَتْ إِنِّي قَدْ كُنْتُ تَجَهَّزْتُ لِلْحَجِّ فَاعْتَرَضَ لِي ‏.‏ فَقَالَ لَهَا رَسُولُ اللَّهِ صلى الله عليه وسلم ‏ "‏ اعْتَمِرِي فِي رَمَضَانَ فَإِنَّ عُمْرَةً فِيهِ كَحِجَّةٍ ‏"‏ ‏.‏
USC-MSA web (English) reference : Book 20, Hadith 67
Arabic reference : Book 20, Hadith 771