What is the significance of God calling Jesus His beloved Son?

The phrase 'Thou art my beloved Son' is rich in theological meaning. It emphasizes not only the special relationship that Jesus has with the Father but also His divinity and messianic role. This declaration, made during the baptism, serves as a public commencement of Jesus' ministry and attests to His identity as the incarnate Son of God, fully pleasing to the Father. From a Reformed perspective, this affirms the belief in the Trinity and the preordained plan of salvation through Christ, who is beloved from eternity and embodies the divine will in His life and ministry.