(a) Abu Abdur Rahman (may Allah have mercy on him) narrates that Sayyiduna Salman (may Allah be pleased with him) passed by some people who were reciting a verse of prostration. The people said: Shall we prostrate as well? He said: No, we did not set out for this.
(b) Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: Prostration is only obligatory upon the one who sat down to listen to it.
(c) Sa'id bin al-Musayyab (may Allah have mercy on him) said: Prostration is only upon the one who is listening to it.
(d) It is reported from Sayyiduna Uthman (may Allah be pleased with him) that prostration is only upon the one who sat for it and is silent.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3768