Jesus spoke about what He shared with the Father and the Holy Spirit in John 16. He spoke with inside knowledge of God's very being. We humans use words like person and personality, identity and community attempting to clarify all the details about how one God could reveal God's very self in three distinct ways. The best explanation I know of is a children's bookthat compared the mystery of God being 3 in 1 to an apple's skin, flesh, and seed as 3 distinct parts of one apple.
For Jesus being one with the Father and the Spirit is normal and natural, but for us this is a mystery. Jesus spoke of the things his friends couldn't yet βαστάζειν bear John 16:12. In faith we know God is one acting in the universe as three. We live with ambiguity about how or where one person of God starts and another stops. This is Jesus' true nature but for us this is a mystery.
Jesus didn't offer a solution to the mystery. It's not a logic puzzle we can solve. Instead He made a promise that the Spirit will ἀναγγελει declare it to you John 16:13-14. The Spirit won't explain away mystery; the Spirit will declare God's work in our lives as Father, Son, and Holy Spirit. The mystery isn't done and gone; but the experience of God working in our lives grows. The Spirit will emphasize God's work as three distinct persons with one common will and one common goal. An old teacher wisely points to the communal nature of God starting with the Holy Spirit.
“The Holy Spirit is always communal. Why? Because God is communal. Being-in-communion. The Spirit joins father and Son. The Spirit joins us to God.” Pat Keifert Talking About Our Faith p62We look for explanations, for the point where one starts and ends. And God isn't worried about that at all. Rather God is at work seeking the redemption of what He's made.
Pax, and thanks for reading.