A.T. Robertson Commentary John 17:8

"for the words which thou gavest me I have given unto them; and they received [them], and knew of a truth that I came forth from thee, and they believed that thou didst send me." — John 17:8 (ASV)

The words (τα ρηματα). Plural, each word of God, as in 3:34, and of Christ (5:47; 6:63,68), while the singular (τον λογον σου) in verses 6,14 views God's message as a whole.

Knew (εγνωσαν). Second aorist active indicative of γινωσκω like ελαβον in contrast with εγνωκαν (perfect) in verse 7. They definitely "received and recognized truly" (αληθως). There was comfort to Christ in this fact.

They believed (επιστευσαν). Another aorist parallel with ελαβον and εγνωσαν. The disciples believed in Christ's mission from the Father (John 6:69; Matthew 16:16). Note απεστειλας here as in verse 3. Christ is God's

Apostle to man (Hebrews 3:1). This statement, like a solemn refrain (Θου διδστ σενδ με), occurs five times in this prayer (verses 8,18,21,23,25).