"For if the honour paid to Him is shared by others, He altogether ceases to be worshipped, since His religion requires us to believe that He is the one and only God"

Lactantius, an early Christian author and advisor to Constantine the Great, is known for his works that defend and explain Christian teaching. The quote you've offered comes from his broader doctrinal discourse, which frequently focuses around the exclusivity and supremacy of Christian praise.

This particular declaration highlights the monotheistic nature of Christianity. Lactantius is arguing that the honor and praise due to God can not be legitimately shared with other beings or deities. If praise is divided or extended beyond the one real God, it jeopardizes the very essence of His divinity and the religion itself. The core of Christian faith, as articulated by Lactantius, is the exclusivity of God as the single, supreme divine being, demanding undistracted praise.

In this context, Lactantius is possibly refuting polytheistic practices, which prevailed in the Roman Empire during his time. By mentioning that God "altogether ceases to be worshipped" if His honor is shared, Lactantius is highlighting how essential the particular devotion to God is to the practice of Christianity. If believers provide worship to other entities, it reduces the individuality and supremacy of the Christian God, possibly leading adherents far from true faith.

In addition, this quote talks to a broader doctrinal and philosophical concept within Christianity: the denial of syncretism, or the mixing of religions and practices from different customs. Christianity, as contended by Lactantius, requires a clear and distinct commitment to one God. This dedication is fundamental to the stability and identity of the Christian religion.

Lactantius's argument can be viewed as a call to purity of faith and practice. It serves as a suggestion to followers that the relationship with God must be singular and foremost, without any other gods or beings sharing in that veneration. In essence, this shows an essential theological assertion of Christianity that stands versus any form of idolatry or polytheism, enhancing the core belief in one, supreme God.