Contradiction with John 8:18
In John 8:18, Jesus speaks of Himself as a witness alongside the Father, whereas in John 15:26, the Spirit of truth is the one who testifies of Jesus.
John 8:18: I am one that bear witness of myself, and the Father that sent me beareth witness of me.
Contradiction with John 16:13
John 16:13 indicates that the Spirit will not speak of himself but will speak what he hears, which could be seen as a contradiction to the idea of testifying directly of Jesus.
John 16:13: Howbeit when he, the Spirit of truth, is come, he will guide you into all truth: for he shall not speak of himself; but whatsoever he shall hear, [that] shall he speak: and he will shew you things to come.
Contradiction with 1 John 5:6
This verse refers to the Spirit as the one who bears witness because the Spirit is truth, which may contrast with John 15:26 where the emphasis is on the Spirit being sent by Jesus.
1 John 5:6: This is he that came by water and blood, [even] Jesus Christ; not by water only, but by water and blood. And it is the Spirit that beareth witness, because the Spirit is truth.
Contradiction with Matthew 28:20
The verse emphasizes Jesus' continual presence with the believers, which could be interpreted as minimizing the role of the Holy Spirit in testifying.
Matthew 28:20: Teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you alway, [even] unto the end of the world. Amen.
Contradiction with Acts 1:8
This verse states that the disciples will receive power and be witnesses after the Holy Spirit comes upon them, focusing on the disciples as witnesses rather than the Spirit.
Acts 1:8: But ye shall receive power, after that the Holy Ghost is come upon you: and ye shall be witnesses unto me both in Jerusalem, and in all Judaea, and in Samaria, and unto the uttermost part of the earth. [power...: or, the power of the Holy Ghost coming upon you]
Paradox #1
Some people see a contradiction between this verse and other parts of the Bible concerning the Holy Spirit's role. In some places, it seems the Spirit is sent by both the Father and Jesus, while in others, it's just by the Father or just by Jesus. This can be confusing on how the different parts of the Trinity work together.
Paradox #2
One possible contradiction or conflict related to John 15:26 could involve different interpretations of the nature of the Holy Spirit. Some religious groups may disagree on whether the Holy Spirit is a distinct person or an impersonal force, leading to differing understandings of its role and presence in the Christian faith.