And Abdullah bin Umar (may Allah be pleased with them both) considered it preferable that the follower should also say the salam at the same time as the imam says the salam.
Hadith Referenceصحيح البخاري / كتاب الأذان (صفة الصلوة) / 838
And Abdullah bin Umar (may Allah be pleased with them both) considered it preferable that the follower should also say the salam at the same time as the imam says the salam.