ONE OF THE FIRST CONCEPTS MATTHEW LEARNS IS THAT THERE IS ONLY ONE GOD - JEHOVAH. SINCE ONLY JEHOVAH'S WITNESSES WORSHIP JEHOVAH, ONLY THEY ARE ACCEPTABLE TO GOD.

"Hence, to seek Jehovah today one must gather around the kingdom of God, doing it unitedly with all his Kingdom witnesses.
What does Zephaniah’s stressing of the need for seeking Jehovah indicate, then? That only by doing so can one find concealment during Armageddon." - Watchtower 1963 Feg 15 p.103

"There is no middle ground.
We are either actively for Jehovah God or actively or tacitly for the gods of this world. Make your choice, and know that your decision means life or death for you." - Watchtower 1965 Feb 15 p.119