When God wrote the words, “So you are My witnesses” (Isaiah 43:12, CSB) He was speaking to the people of the Old Testament era. In this section of Isaiah, He challenges the false gods to stand trial. They fail to meet the test. When He calls forth His own witnesses they are able to measure up. It is His people, who at the trial, tell of His mighty works.
Now, as the trial progresses, part of the evidence given has to do with the fact that He is the only God—that He is the one Who is from eternity past is emphasized. Isaiah writes,
No god was formed before Me, and there will be none after Me.
In the very passage from which Jehovah’s Witnesses obtain their name, it is made clear that no god will be formed after Yahweh. Yet, they are the very ones who say the opposite, calling Jesus “a God” Who was formed afterwards.
Moreover, in v. 11, we are told that “there is no other Savior but Me”. And, yet, in Luke 2:11 Jesus is said to be the Savior!
How ironic it is that two of the false statements about God made by the JWs are refuted in the very passage from which they wrongly take their name! Next time they appear at your door, you might enlighten them of the fact, and point them to Christ as Savior.