Have you read
Colossians 1?
15 The Son is the image of the invisible God, the firstborn over all creation. 16 For in him all things were created: things in heaven and on earth, visible and invisible, whether thrones or powers or rulers or authorities; all things have been created through him and for him. 17 He is before all things, and in him all things hold together. 18 And he is the head of the body, the church; he is the beginning and the firstborn from among the dead, so that in everything he might have the supremacy. 19 For God was pleased to have all his fullness dwell in him, 20 and through him to reconcile to himself all things, whether things on earth or things in heaven, by making peace through his blood, shed on the cross.
God in his grace provides salvation to the world in a new covenant.
What better way to bless the world and with the good news of God's saving grace than to arrive and dispense it himself as the prophecied Messiah.
And to inform the people of this and having the assurance this is God and his good news delivered into the world, his angel informed Mary she was to name his only begotten son, Immanuel.