Your question, How can we know the truth in Christ?
I’m writing this so you can distinguish between truth and deception, between light and darkness. Between understanding and human reasoning, between wisdom and ignorance, ignorance is not merely the absence of knowledge. It is a state of mind that leads to eternal damnation.
Let me attempt to explain the distinction between knowledge and understanding. For instance, consider a child learning his ABCs or counting from one to a hundred. They have committed these to memory, but they lack comprehension of their purpose. Subsequently, they may declare, “I understand.” But this is knowledge without understanding. The same principle applies to God’s word. A person can learn the Bible’s words, memorize them, yet still fail to grasp their meaning.
Here’s an example of the Father revealing his truth to someone. When Christ asked his disciples about his identity, Peter responded with the following.
Matthew 16:15-17 “He said unto them, But whom say you that I am? 16 And Simon Peter answered and said, You are the Christ, the Son of the living God. Jesus responded and said to him, “Blessed are you, Simon Barjona. For flesh and blood has not revealed it to you, but my Father who is in heaven.” In Peter’s case, it was the Father who imparted his understanding to him.
As to Pilate his knowledge of Jesus was based on what he was told by other.
John 18:33-34 33 Then Pilate entered into the judgment hall again, and called Jesus, and said unto him, Art thou the King of the Jews? 34 Jesus answered him, Sayest thou this thing of thyself, or did others tell it thee of me?
Now if Pilate truly believed Jesus was a king the Son of God, he would not have crucified him. Listen to what the Apostle wrote. (See comment for the rest)