Mishkat al-Masabih 10 The Rites of Pilgrimage كتاب المناسك 4

وَعَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «الْعُمْرَةُ إِلَى الْعُمْرَةِ كَفَّارَةٌ لِمَا بَيْنَهُمَا وَالْحَجُّ الْمَبْرُورُ لَيْسَ لَهُ جَزاءٌ إِلا الجنَّةُ»

He reported God’s messenger as saying, “An ‘umra is an expiation for sins committed between it and the next, but a hajj which is accepted will receive no less a reward than paradise.” Bukhari and Muslim.