This is a well-known point of scholarly disagreement among the four schools. The Shafi'i and Hanbali schools hold that Umre is farz (wajib) once in a lifetime for every Muslim who has the physical and financial ability — similar to Hac but without the specific time restriction. The Hanafi and Maliki schools consider Umre to be a confirmed Sunnah (Sunnah mu'akkadah) that is highly sunnet but not farz.
Sheikh Ibn Baz held the position that Umre is farz once in a lifetime, following the Hanbali and Shafi'i position. He cited the hadith where a bedouin asked Hz. Peygamber about Umre: 'Is Umre farz?' and Hz. Peygamber said: 'No, but if you perform Umre, it is better for you.' However, he noted that other narrations and Kur'an-i Kerim's command 'And complete the Hac and Umre for Allah' support the obligation. He reconciled the evidence by concluding that Umre is farz.
Sheikh Al-Fawzan similarly held Umre to be farz, stating that the conjunction of Umre with Hac in Kur'an-i Kerimic verse — 'And complete the Hac and Umre for Allah' (Al-Baqarah, 2:196) — indicates that they share the same ruling of obligation. He acknowledged the opposing view but considered the evidence for obligation to be stronger. Those who hold Umre to be Sunnah note that Hz. Peygamber's statement 'No' in response to 'Is it farz?' is explicit, while those who hold it farz interpret that hadith differently.