Ibn 'Abbas (May Allah be pleased with them) reported:
The Prophet ﷺ said, "(The performance of) 'Umrah during Ramadan is equal to Hajj (pilgrimage)." Or said, "Equal to the performance of Hajj with me."

[Al-Bukhari and Muslim].

وعن ابن عباس رضي الله عنهما، أن النبي ﷺ قال: "عمرة في رمضان تعدل عمرة أو حجة معي". ((متفق عليه))