Is there any proof in the New Testament that the apostles and early followers of Yahushua taught and spoke in the sacred name Yahweh?
Many would say no for a variety of reasons, one of which is that the name Yahweh is not found in any existing Greek manuscripts.
Is this really the total truth?
Proof that the original apostles adhered to the sacred name doctrine is found in numerous places in the New Testament. James shows his respect for the sacred name when he warns the disciples against favoring a rich man over someone poor:
But you dishonoured the poor. Do not the rich oppress you, and do (not) they drag you before tribunals? Do not they blaspheme the good name which is called upon you? (James 2:6-7)