He who has the bride is the bridegroom; but the friend of the bridegroom, who stands and hears him, rejoices greatly because of the bridegroom's voice. This, my joy, therefore is made full.

 It is John's grief that so few accept the message that Jesus brought; but when a man does accept it, he attests the fact that in his belief the word of God is true. In the ancient world, if a man wished to give his full approval to a document, such as a will or an agreement or a constitution, he affixed his seal to the foot of it. The seal was the sign that he agreed with this and regarded it as binding and true. So when a man accepts the message of Jesus, he affirms and attests that he believes what God says is true. 