We know Jesus suffered while on earth: the persecution He endured, despising the shame, and the ultimate sacrifice at the cross.
John describes the glory of Jesus in the Revelation, and of all the terms that could have been used––sovereign Lord, Prince of peace, Mighty God, Creator, or Christ––John chose “Lamb.” Why use Lamb? Because He was the sacrifice made for the world. Suffering cannot be separated from the glory.
Paul reminds us that the sufferings of this present life are not worthy to be compared to the glory that will be revealed to us, but suffering comes first.