What does it mean to worship in truth?
John 4:23-24 But the hour cometh, and now is, when the true
worshippers shall worship the Father in spirit and in truth: for the
Father seeketh such to worship him. God is a Spirit: and they that
worship him must worship him in spirit and in truth.
Jesus announced a change in worship. Location centered worship was to fade away and be replaced by worship in spirit and truth. In a way "spirit" is the means by which we can worship as opposed to coming to a physical location.
Romans 8:15-16 For ye have not received the spirit of bondage again to
fear; but ye have received the Spirit of adoption, whereby we cry,
Abba, Father. The Spirit itself beareth witness with our spirit, that
we are the children of God:
We have an example of how to worship without truth.
Luke 18:11-12 The Pharisee stood and prayed thus with himself, God, I
thank thee, that I am not as other men are, extortioners, unjust,
adulterers, or even as this publican. I fast twice in the week, I
give tithes of all that I possess.
We also have an example of worship in truth.
Luke 18:13 And the publican, standing afar off, would not lift up so
much as his eyes unto heaven, but smote upon his breast, saying, God
be merciful to me a sinner.
The Pharisee thought he was righteous and was probably factual about his fasting and tithing. However, the truth is that trying to impress God with our accomplishments is foolish. If we look at ourselves in truth, we can only respond with humility.