How do we know the doctrine of God's oneness is true?

The truth of God's oneness is foundational in both the Old and New Testament teachings, as seen in Mark 12:29 and reinforced in passages like 1 Corinthians 8:5-7. This doctrine counters the polytheistic beliefs of the surrounding cultures, highlighting that the God of Israel is unique. Jesus' affirmation of this truth underscores its centrality in understanding the nature of God and guiding our worship and devotion. Believers must recognize that love for the one true God is fundamental to their faith and practice.