It is an attribute of truthful words that they be beneficial and instructive, not just factually true. That is probably the sense of truth meant by these passages. The second group of passages deal with honesty as promise-keeping. In the Abrahamic faiths, promises have often been sealed by oaths, sworn in the name of God. But as Jesus' admonition illustrates, oaths can be abused and sworn falsely, particularly when the person does not truly believe in the God to whom he swears.
All religions elevate promise-keeping as a central virtue of human relations.
The last group of passages are on the topic of expediency. In leading people to recognize the truth of religion, expediency may also be required, for the truth is sometimes hidden in a package that is outwardly unseemly. The Buddhist doctrine of Expedient Devices, or Skill in Means, as expressed in passages from the Lotus Sutra, attempts to reconcile the various schools of Buddhism by showing that Buddha preached various doctrines according to people's temperaments and inclinations. It is first necessary to grasp the relative truth of worldly phenomena before one can comprehend the absolute truth which is beyond appearances. The seal of God is truth.