Jesus says that the Father has given the Son 'power over all flesh' so that he may give eternal life to those the Father has given him.
Jesus in Context
Authority Over All Flesh
The KJV phrase 'power over all flesh' uses exousia, the language of authority or rightful jurisdiction, and 'all flesh' is a biblical idiom for humanity.
Introduction
Historical and Cultural Context
The Greek exousia commonly denotes authority, right, or jurisdiction rather than raw physical power. The expression 'all flesh' has deep biblical roots as a way of referring to mortal humanity collectively. Together the phrases describe a universal scope of authority bestowed on the Son. John's wording distinguishes the Father who gives authority and the Son who exercises it while making the scope extraordinarily comprehensive.
Why It Matters
The older English wording can sound as though Jesus merely possesses superior strength. The language is more judicial and royal: he has been granted authority over humanity.
Within the prayer, that authority is directed toward giving eternal life, joining universal sovereignty with the saving mission entrusted to the Son.