Hadith: O Messenger of Allah, how come the people have ended their state of Ihrām for ‘Umrah while you have not? he said: I have applied to my hair that which would make it matted and marked my sacrificial animal, and I will not end my Ihrām until I slaughter

عن حَفْصَة زَوْج النَّبِي رضي الله عنها قالت: «يَا رَسُولَ اللَّه، مَا شَأن النَّاس حَلُّوا مِنَ العُمرَة، وَلَم تَحِلَّ أنت مِنْ عُمْرَتِكَ؟ فَقَال: إنِّي لَبَّدْتُ رَأْسِي، وَقَلَّدتُ هَدْيِي، فَلا أَحِلُّ حَتَّى أَنْحَرَ».
[صحيح] - [متفق عليه]

Hafsah, one of the Prophet's wives, reported that she said: "O Messenger of Allah, how come the people have ended their state of Ihrām for ‘Umrah while you have not?" He said: "I have applied to my hair that which would make it matted and marked my sacrificial animal, and I will not end my Ihrām until I slaughter."
[Authentic hadith] - [Narrated by Bukhari & Muslim]

Explanation

The Prophet (may Allah's peace and blessings be upon him) entered the state of Ihrām in the Farewell Pilgrimage for both ‘Umrah and Hajj. He led his sacrificial animal and applied something to his hair that would hold it back from spreading because the period of his Ihrām would be long. Some of his Companions did the same, while some made Ihrām for ‘Umrah (in the months of Hajj) intending to perform Hajj thereafter, and most of them did not lead their sacrificial animals with them, while some of them did. When they arrived at Makkah and made Tawāf and Sa‘i, he ordered those who had not led their sacrificial animals from among those who were performing Hajj only or comibning Hajj and ‘Umrah without a break in between to cancel their Hajj and make it an ‘Umrah only and end their Ihrām. As for him and those who led their sacrificial animals, they remained in the state of Ihrām. Thereupon, his wife Hafsah asked him why people had ended their Ihrām while he had not. He replied: "Because I have applied to my hair that which would make it matted and marked my sacrificial animal and drove it, and this prevents me from ending my Ihrām until the sacrificial animal reaches its place, which is the day that ends Hajj, the Day of Slaughter."