Shaikh Ibn Bāz (rahimahullāh) said: “If it is only a few drops of blood or a small amount then it is overlooked (and does not harm the prayer). However, if it is a large amount of bleeding, then he should stop the Prayer until he changes his garments or washes them. As for a small amount of drops, then they are pardoned because Allah stated: “Be dutiful to Allah and fear Him as much as you are able.” (At-Taghābun: 16) And He said: “Allah does not burden a person except that he can bear it.” (Al-Baqrah: 286) And He said: “Allah did not place upon you hardship in the Religion.” (Al-Hajj: 78), He is the Perfect, Most High. So something small, a few drops of blood, vomit or pus (on garments during prayer) are overlooked because Allah (the Mighty and Majestic) has removed hardships from this Ummah.”
(Source: Nūr ‘alad-Darb)
إذا كان قطرات يسيرة يعفى عنها، وأما إذا كانت كثيرة يقطع الصلاة حتى يبدل الثوب ويغسلها، أما إذا كانت قطرات يسيرة يعفى عنها؛ لأن الله جل وعلا يقول: فَاتَّقُوا اللَّهَ مَا اسْتَطَعْتُمْ [التغابن:16] .. لا يُكَلِّفُ اللَّهُ نَفْسًا إِلَّا وُسْعَهَا [البقرة:286] ويقول: وَمَا جَعَلَ عَلَيْكُمْ فِي الدِّينِ مِنْ حَرَجٍ [الحج:78] سبحانه وتعالى، فالشيء اليسير يعفى عنه قطرات من دم أو قيح أو صديد هذا يعفى عنها؛ لأن الله جل وعلا رفع الحرج عن هذه الأمة، نعم.