Jesus asks that his followers ultimately be with him and behold his glory, adding that the Father loved him 'before the foundation of the world.'
The prayer again reaches beyond earthly history into the relationship of Father and Son before creation.
'Foundation of the world' is a biblical expression for the beginning or creation of the world. To place the Father's love for the Son before that foundation is to describe a relationship prior to created history. The statement complements John 17:5, where Jesus speaks of the glory he had with the Father before the world existed. The language is personal: the Father loved the Son, not merely a future role or abstract plan.
The temporal idiom strengthens John's high Christology. Jesus' relationship with the Father does not begin at Bethlehem, baptism, or the start of public ministry.
The Gospel portrays divine love and shared glory as belonging to Father-Son fellowship before the creation of the world.