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]. (ES)
App reference (ES): Book 11, Hadith 8 (ES)
Arabic/English book reference (ES): Book 11, Hadith 1278 (ES)