ENOfficial
Ibn `Umar said: The Muslims will soon be besieged up to Medina, so that their most distant frontier outpost will be Salah which is near Khaibar. Abu Dawud transmitted it.
Source: sunnah.com
Other translations
Arabic
وَعَنِ ابْنِ عُمَرَ قَالَ: يُوشِكُ الْمُسْلِمُونَ أَنْ يُحَاصَرُوا إِلَى الْمَدِينَةِ حَتَّى يَكُونَ أَبْعَدَ مَسَالِحِهِمْ سَلَاحٌ وَسَلَاحٌ: قَرِيبٌ مِنْ خَيْبَرَ. رَوَاهُ أَبُو دَاوُد
sunnah.com