How do we know Jesus declares God?

According to John 1:18, Jesus Christ, who is in the bosom of the Father, declares God. This means He reveals God's character and attributes fully. Throughout His ministry, Jesus demonstrated God's mercy and truth, for instance, by raising a widow’s son in Nain, showcasing compassion and divine authority. His words and actions not only reveal who God is but also affirm the fulfillment of God’s promises and character, which are further seen through the historical accounts of His life in the Gospels.