For as the Father has life in himself, so he has granted the Son also to have life in himself (Jn 5:26)
This verse is often cited to establish the ontological subordination of the Son to the Father, according to which the Father is the fons deitas. However, “in himself” doesn’t carry that connotation in Johannine usage, and the “life” in question is hardly synonymous with the divine essence. As one commentator explains:
The form of Jesus’ next pronouncement echoes that of verse 21: “For just as the Father has life in himself, so too he gave to the Son to have life in himself” (italics added). What does it mean to “have life,” and what does it mean to have it “in himself”?…“In himself” [en heauto] adds little to this and should not be overinterpreted…To have “life in oneself” is not something only the Father and the Son share, but something believers can claim as well. Those who “eat the flesh of the Son of man” can be said either to “have life in themselves” [echete zoen en heautois] (6:53), or simply to “have eternal life” (v54). The two expressions mean the same thing: eternal life is theirs as an assured present possession, and that is all Jesus is saying here about himself and the Father.
J. R. Michaels, The Gospel of John (Eerdmans 2010), 318.