And now I am coming to you is repeated from verse 11.

The phrase these things is best limited to the contents of Jesus’ prayer so far, and not extended to include the entire discourse of Chapters 14–17.

In the world means “while I am still in the world,” a reference to the time left before Jesus’ departure to the Father.

They refers to Jesus’ disciples.

Might have joy in their hearts, in all its fullness (compare 15.11 and 16.24) is more literally “that they may have my joy fulfilled in themselves” (Revised Standard Version). New American Bible translates “that they may share my joy completely” and New English Bible “so that they may have my joy within them in full measure.” Goodspeed renders “in order that they may have the happiness that I feel fully realized in their own hearts.” In the context my joy means “the joy which I experience.” In some languages one cannot speak of having another person’s joy in his own heart. To communicate this concept, it is necessary to indicate the possibility of similar experience, for example, “that they may be completely happy in their hearts in the same way that I am completely happy.”

Quoted with permission from Newman, Barclay M. and Nida, Eugene A. A Handbook on the Gospel of John. (UBS Handbook Series). New York: UBS, 1980. For this and other handbooks for translators see here .