'Drift' in the Bible

For this reason [that is, because of God’s final revelation in His Son Jesus and because of Jesus’ superiority to the angels] we must pay much closer attention than ever to the things that we have heard, so that we do not [in any way] drift away from truth.

how will we escape [the penalty] if we ignore such a great salvation [the gospel, the new covenant]? For it was spoken at first by the Lord, and it was confirmed to us and proved authentic by those who personally heard [Him speak],