Sunan an-Nasa'i, Volume 1, Book 9, Hadith 766 (DarusSalam)

It was narrated that Salamah bin Al-Akwa said: " I said: 'O Messenger of Allah, I go hunting wearing nothing but a single shirt. Can I pray in it?' He said: 'Fasten it to yourself even with a thorn.'"

أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا الْعَطَّافُ، عَنْ مُوسَى بْنِ إِبْرَاهِيمَ، عَنْ سَلَمَةَ بْنِ الأَكْوَعِ، قَالَ قُلْتُ يَا رَسُولَ اللَّهِ إِنِّي لأَكُونُ فِي الصَّيْدِ وَلَيْسَ عَلَىَّ إِلاَّ الْقَمِيصُ أَفَأُصَلِّي فِيهِ قَالَ ‏ "‏ وَزُرَّهُ عَلَيْكَ وَلَوْ بِشَوْكَةٍ ‏" ‏ ‏.‏

sunnah.com