What is the meaning of John 17:21?

* The two F.O.G. Bibles & Commentary below are currently a work in progress.

that all of them may be one, as You, Father, are in Me, and I am in You. May they also be in Us, so that the world may believe that You sent Me.

Berean Standard Bible (BSB)

that they may all be one; even as you, Father, are in me, and I in you, that they also may be one in us; that the world may believe that you sent me.

World English Bible (WEB)

That{G2443} they all{G3956} may be{G5600}{(G5753)} one{G1520}; as{G2531} thou{G4771}, Father{G3962}, art in{G1722} me{G1698}, and I{G2504} in{G1722} thee{G4671}, that{G2443} they{G846} also{G2532} may be{G5600}{(G5753)} one{G1520} in{G1722} us{G2254}: that{G2443} the world{G2889} may believe{G4100}{(G5661)} that{G3754} thou{G4771} hast sent{G649}{(G5656)} me{G3165}.

Strong's King James

(21) In order to all be one, even as You, Abba-Father in Me and I in You so that they also be in Us so that the world believes that You sent Me.

The F.O.G*

[21] Father, may they all experience such perfect unity that the world will be stunned into recognition – just as You and I are one, may they live in such supernatural harmony that their unity becomes evidence that You sent Me.

The F.O.G Paraphrase

that they all may be one, as Thou Father art in me, and I in Thee; that they also in us may be one, that the world may believe that Thou didst send me.

Young's Literal Translation