1 John 5:8

The Holy Spirit [through His Word], and the water [through His immersion] and the blood [through His crucifixion]; and these three agree together [in giving testimony about Him].

Matthew 26:26-28

And as they were eating, Jesus took a [small] loaf of bread, asked God's blessing on it, then broke it and gave pieces to His disciples and said, "Take some and eat it; this is [i.e., represents] my [physical] body."

Matthew 28:19

So, as you go, make disciples out of people from all the nations, then immerse believers [See Mark 16:15-16] into the name of [i.e., to enter a relationship with] the Father, and the Son and the Holy Spirit.

Mark 14:56

For many persons gave false testimony against Him, but their stories did not harmonize.

John 15:26

"But the Helper will come, that is, the Holy Spirit of truth [i.e., who reveals truth]. He comes from the Father and I will send Him to you from the Father. [When He comes] He will give testimony about me.

Acts 2:2-4

Suddenly a rushing sound, like a fierce wind blowing, came from the sky above them, and [its noise] filled the entire house where they were sitting.

Acts 15:15

And this was predicted by the message of the prophets when they wrote [Amos 9:11ff],

Romans 8:16

The Holy Spirit Himself bears testimony [along] with our [human] spirit that we are the children of God.

2 Corinthians 1:22

He has placed His seal of ownership upon us by giving us the down payment of the Holy Spirit [to live] in our hearts.

Hebrews 6:4

[These are people] who were once enlightened [by the Gospel message], who had experienced the gift from heaven [i.e., forgiveness, never ending life, etc. See Rom. 6:23], who had partaken of the Holy Spirit [See Acts 2:38],

Hebrews 13:12

Therefore, Jesus also suffered outside of the gate [i.e., of Jerusalem] so that He could make people holy through [the shedding of] His own blood.

1 Peter 3:21

This water prefigured immersion [into Christ], which now also saves you, not by removing dirt from the [physical] body, but [by serving] as an appeal [or, "pledge"] to God for a clear conscience through the raising of Jesus Christ from the dead.

1 John 5:6-7

This Jesus is the one whose coming [to earth was introduced] by water [at His immersion. See Matt. 3:13] and [completed] by blood [at His crucifixion, John 19:17-37]. He did not come by the water only, but by the water and by the blood. And it is the Holy Spirit who gives testimony [at both of these events], because the Holy Spirit is [always] the truth. [See John 16:13].

Treasury of Scripture Knowledge

Summary

And there are three that bear witness in earth, the spirit, and the water, and the blood: and these three agree in one.

There

Bible References

There

1 John 5:7
For there are three who give their testimony [about Jesus]:

The spirit

1 John 5:6
This Jesus is the one whose coming [to earth was introduced] by water [at His immersion. See Matt. 3:13] and [completed] by blood [at His crucifixion, John 19:17-37]. He did not come by the water only, but by the water and by the blood. And it is the Holy Spirit who gives testimony [at both of these events], because the Holy Spirit is [always] the truth. [See John 16:13].
Matthew 26:26
And as they were eating, Jesus took a [small] loaf of bread, asked God's blessing on it, then broke it and gave pieces to His disciples and said, "Take some and eat it; this is [i.e., represents] my [physical] body."
Matthew 28:19
So, as you go, make disciples out of people from all the nations, then immerse believers [See Mark 16:15-16] into the name of [i.e., to enter a relationship with] the Father, and the Son and the Holy Spirit.
John 15:26
"But the Helper will come, that is, the Holy Spirit of truth [i.e., who reveals truth]. He comes from the Father and I will send Him to you from the Father. [When He comes] He will give testimony about me.
Romans 8:16
The Holy Spirit Himself bears testimony [along] with our [human] spirit that we are the children of God.
Hebrews 6:4
[These are people] who were once enlightened [by the Gospel message], who had experienced the gift from heaven [i.e., forgiveness, never ending life, etc. See Rom. 6:23], who had partaken of the Holy Spirit [See Acts 2:38],

The water

Acts 2:2
Suddenly a rushing sound, like a fierce wind blowing, came from the sky above them, and [its noise] filled the entire house where they were sitting.
2 Corinthians 1:22
He has placed His seal of ownership upon us by giving us the down payment of the Holy Spirit [to live] in our hearts.

The blood

Hebrews 13:12
Therefore, Jesus also suffered outside of the gate [i.e., of Jerusalem] so that He could make people holy through [the shedding of] His own blood.
1 Peter 3:21
This water prefigured immersion [into Christ], which now also saves you, not by removing dirt from the [physical] body, but [by serving] as an appeal [or, "pledge"] to God for a clear conscience through the raising of Jesus Christ from the dead.

And these

Mark 14:56
For many persons gave false testimony against Him, but their stories did not harmonize.
Acts 15:15
And this was predicted by the message of the prophets when they wrote [Amos 9:11ff],