Sanctify them through thy truth: thy word is truth.
John 17:17 KJV /Geneva
This is one of those verses, for me, that no other Bible translation works. I did not do a search of all the translations out there, but the ones I did look up had all changed the verb in the first part of the sentence. Changing the verb affected the meaning of the whole thing, too.
Sanctify simply means to "set apart; make holy". We, who believe in Christ, are set apart from the rest.
What sets us apart? God's truth. Jesus.
This means that we are not judging others. We are not telling others we hold the market on salvation. That is not of us. It is of God.
Recently, I have seen a Christian who stated the Truth—that Jesus is the only way to spend eternity with God in Heaven—be called judgmental. Nothing of the sort was happening. The Christian was simply telling the truth, as according to God's Word. Please know, we Christians do not wish to see anyone spend eternity separated from God. We are simply saying what the Bible says.
Have I seen Christians declare they know the Truth in an arrogant way to others? Yes, I have. I am not advocating that approach at all. Who wants to listen to a smug know-it-all?
In humility, but with confidence, is how we should share the Truth with others who share this world with us.