'Ubida b. Samit reported that when wahi (inspiration) descended upon Messenger of Allah ﷺ, he felt a burden on that account and the colour of his face underwent a change.
كَانَ نَبِيُّ اللَّهِ ﷺ إِذَا أُنْزِلَ عَلَيْهِ الْوَحْىُ كُرِبَ لِذَلِكَ وَتَرَبَّدَ وَجْهُهُ