You may say: how can I tell? [that the God whom we seek to worship is the God of the Bible, the triune Jehovah?] Well, the test is this. […] Do I look habitually to the person and work of the Lord Jesus Christ as showing me the final truth about the nature and the grace of God? Do I see all the purposes of God as centring upon him?
J.I. Packer,Knowing God, at 54-55.