What does John 17:22 mean?

All statements in the Bible are meant to be understood in context—this verse is no exception. Jesus' references to "glory" here cannot be interpreted properly without noticing how He used the concept at the beginning of this High Priestly Prayer (John 17:1). In that statement, Jesus noted that "the hour has come" for Him to be crucified (John 12:32–33). At least in part, Jesus means the "glory" of the cross is something He is giving to the church (John 3:16; 1 Timothy 2:5–6). He is not elevating believers to His level or bestowing all aspects of His divine glory on us.

There is a sense in which Christians are given glory (2 Corinthians 3:18), in a more direct manner, by virtue of salvation (Romans 6:4; 8:17, 30; 1 John 3:1–2). Again, however, Jesus ties the purpose of this to Christian unity (John 17:21). The primary identifier of a Christian, among the unbelieving world, is supposed to be love (John 13:34–35). This does not extend to endorsing sin or false teaching (Galatians 1:8; 2 Timothy 3:16; 1 Corinthians 5:11). It does mean that self-professed Christians are supposed to demonstrate the goodness of God (Matthew 5:13–16), helping others come to faith. Truthful unity (Colossians 3:14) is intended to prove that Christians are following God (John 17:23).