Again, John 4:23,24 couldn't be anymore explicit that the Father is the Spirit. It's actually very basic logic.
- True worshipers worship the "Father" in spirit and truth
- False worshipers worship others
- Yet God must be worshipped in spirit and truth
- Therefore Jesus equates God with the Father only
- Since God is a Spirit, the Father is a Spirit
- Father = Holy Spirit
This is what Jesus taught and it waste-bins the trinity.
Let's start looking at some examples to supplement Jesus' point about the Father being the (Holy) Spirit.
"No one knows the Son except the Father" is a statement that excludes the Holy Spirit if the Holy Spirit is a third person. Since the Father is the Spirit, there are clear reasons why Jesus omitted the Spirit as it would be redundant.
Matthew 11
27All things have been entrusted to Me by My Father.
No one knows the Son except the Father, and no one knows the Father except the Son and those to whom the Son chooses to reveal Him.
Let's not leave it there. Again, can you find any clear example of the Father and the Holy Spirit having a back and forth conversation?