Surah Al-Baqarah 2:196 البقرة

Perform Hajj and Umrah completely, seeking only Allah's pleasure. If you are prevented from completing them by illness or an enemy, then you should sacrifice what is easily available of sacrificial animals, such as camels, cows, or sheep, before you take off your Ihram, and do not shave your heads or cut your hair until the sacrificial animals have reached the place where slaughtering them is permissible. If you are prevented from entering the Sacred Sanctuary, then perform the slaughter (of the sacrificial animal) wherever you have stopped; yet if you can enter the Sacred Sanctuary, perform it on the Day of Sacrifice (10th of Dhul-Hijjah) or within the following days of tashriq (11th, 12th and 13th of Dhul-Hijjah). Whoever among you is ill or has a problem with his hair or head, such as lice or the like, and shaves his head for that reason, then that is not a problem. He should, however, fast for three days, or feed six poor people from the area of the Sanctuary, or sacrifice a sheep to be distributed among the poor within the Sanctuary. If you are living in times of peace, then whoever takes the opportunity to perform Umrah in the months of Hajj, enjoying in between those things that are not allowed when performing the pilgrimages, should sacrifice whatever is easily available: a sheep or a seventh of a camel or cow. If they cannot make a sacrifice, they must fast for three days during the days of Hajj to make up for it and seven more days when they return home, making ten days altogether. This practice of having a break between Umrah and Hajj and sacrificing an animal or fasting for those unable to make a sacrifice is only for people who do not live within or close to the Sanctuary of the Sacred Mosque. As for those who live within the Sanctuary or close to it, they do not do this because they do not need to due to their constant presence and enjoyment of being able to make Umrah or Tawaf freely any other time of the year. Be mindful of Allah by following what He makes sacred law, respecting His limits, and understanding that Allah is firm in punishing those who go against what He instructs.