It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) said: "Whoever hears the call to prayer (adhan) and does not come (to the mosque), there is no prayer for him (that is, it is not complete)." Imam al-Hakim says that Ghundar and most of Shu'bah's students narrated this hadith as mawquf (stopping at the Companion), but Hushaym and Qurad Abu Nuh narrated it as connected, and both of them are trustworthy, so their marfu' (attributed to the Prophet) narration is the one relied upon. This hadith is sahih (authentic) on the condition of the two Shaykhs, but they did not record it.