I say, and with God's help: The enemy that prevents him from accessing water may be human, such as a sinful person, or a creditor who holds him back because the creditor is at the water and the debtor fears imprisonment, or it may be a captive who is prevented by the infidels from performing ablution, or he may be told: If you perform ablution, I will kill you. It may also be a non-human entity, such as a wild animal, a snake, or fire. In all these cases, it is permissible for him to perform tayammum (dry ablution). However, if the obstacle to performing ablution is from the direction of people, he should repeat the prayer once the obstacle is removed. Refer to: Rad al-Muhtar 1: 106, in the explanation of Al-Wiqayah, p. 113, from Al-Dhakirah Al-Barhaniyah, q. 7/, and God knows best.