What is the reason for the shiver that comes over a worshiper when saying "Amen" to the preacher's supplication during the Friday sermon?

This state might be due to being affected by the sermon and what it contained of verses, admonitions, promises, warnings, and the remembrance of Allah Almighty, in accordance with His saying: "Their skins shiver therefrom, of those who fear their Lord; then their skins and their hearts soften to the remembrance of Allah." Or it might be due to another ordinary reason. In both cases, praise Allah and thank Him, and beware of arrogance and conceit.