Allah's Messenger (ﷺ) said, "(The performance of) `Umra is an expiation for the sins committed (between it and the previous one). And the reward of Hajj Mabrur (the one accepted by Allah) is nothing except Paradise."
Sahih al-Bukhari Book 26, Hadith 1
← Previous Hadith Safiya got her menses on the night of Nafr (departure from Hajj), and she said, "I see that I will detain you." The Prophet (ﷺ) said, "Aqra Halqa! Did she perform the Tawaf on the Day of Nahr (slaughtering)?" Somebody replied in the affirmative. He said, "Then depart." (Different narrators mentioned that) `Aisha said, "We set out with Allah''s Apostle (from Medina) with the intention of performing Hajj only. When we reached Mecca, he ordered us to finish the Ihram. When it was the night of Nafr (departure), Safiya bint Huyay got her menses. The Prophet (ﷺ) said, "Halqa Aqra! I think that she will detain you," and added, "Did you perform the Tawaf (Al-Ifada) on the Day of Nahr (slaughtering)?" She replied, "Yes." He said, "Then depart." I said, "O Allah''s Apostle! I have not (done the Umra)." He replied, "Perform `Umra from Tan`im." My brother went with me and we came across the Prophet (ﷺ) in the last part of the night. He said, "Wait at such and such a place."

Sahih al-Bukhari Book 25, Hadith 247 Next Hadith → `Ikrima bin Khalid asked Ibn `Umar about performing `Umra before Hajj. Ibn `Umar replied, "There is no harm in it." `Ikrima said, "Ibn `Umar also said, 'The Prophet (ﷺ) had performed `Umra before performing Hajj.'"

Narrated `Ikrima bin Khalid:

"I asked Ibn `Umar the same (as above)."

Sahih al-Bukhari Book 26, Hadith 2