Dietrich Bonhoeffer from his Cost of Discipleship:
Because the first and last concern of truthfulness is the revealing of persons in their whole being, in their evilness before God, such truthfulness is resisted by the sinner. That is why it is persecuted and crucified. The truthfulness of the disciples has its sole basis in following Jesus, in which he reveals our sins to us on the cross. Only the cross as God’s truth about us makes us truthful. Those who know the cross no longer shy away from any truth. Those who live under the cross can do without the oath as a commandment establishing truthfulness, for they exist in the perfect truth of God.
There is no truth toward Jesus without truth toward other people. Lying destroys community. But truth rends false community and founds genuine fellowship. There is no following Jesus without living in the truth unveiled before God and other people.