Final answer:
The idea that there is only one true God and any conflicting claims are false refers to religious orthodoxy within monotheistic belief systems like Judaism, Christianity, and Islam.
Step-by-step explanation:
The statement suggests adherence to a form of monotheism, which is a belief in one true God. Monotheistic religions, such as Judaism, Christianity, and Islam, uphold the belief in a single, omnipotent deity. Claims contrary to this belief are seen as false within these faith traditions. The concept you're describing is an aspect of religious orthodoxy, expressing that there is one truth and all deviations are heretical.
In the context of monotheistic religions, deviations such as polytheism—belief in multiple gods—or pantheism, which identifies God with the universe, are regarded as incorrect. Variations like the Holy Trinity in Christianity complicate the strict definition of monotheism but are still understood as a form of it by adherents. Understanding truth claims in religion also involves examining philosophical theories of truth, such as Aristotle's definition where a statement is true if it accurately reflects reality.