Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) said that the Messenger of Allah (peace and blessings be upon him) said: "Whoever hears the call to prayer and does not come to the prayer without any excuse, the prayer that he prayed will not be accepted from him." They said: "What is an excuse?" He said: "Fear or illness."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 5047