John 5:39  Search the scriptures; for in them ye think ye have eternal life: and they are they which testify of me.  Jesus is talking to a very religious group of people, the Jews.  They knew the Word of God, but they did not know the God of the Word.
Huge difference!  Even Satan, when tempting Jesus, tried to use God’s word against Him. This same religious group sought to kill Jesus… Matthew 5:18 Therefore the Jews sought the more to kill him, because he not only had broken the sabbath, but said also that God was his Father, making himself equal with God.
These people were very sincere.  Just remember,  it is possible to be sincerely wrong.
I think of many religious groups today that are no doubt sincere, yet they are trying to get to Heaven apart from the death and resurrection of Jesus Christ our Lord.  It will never work out for them.  Two men were praying in the temple, and one man was full of pride, the other humbled himself.   The humble man went down to his house justified!  Eternity is way too long to be wrong!  Jesus is the Son of the living God!  He’s coming!  Do you think you have eternal life… or do you KNOW IT!  Paul said…  Nevertheless, I am not ashamed: for I know whom I have believed, and am persuaded that he is able to keep that which I have committed unto him against that day. Amen. Pastor