We Believe in the Only-Begotten Son, Part I

And in one Lord, Jesus Christ, the only Son of God,

eternally begotten of the Father.

Light from Light, true God from true God,begotten, 

not made, one in being with the Father. (Symbol of Faith)

You are without beginning,invisible, incomprehensible, 

uncircumscribed, unchangeable,the Father of our Lord, Jesus Christ 

... he is the image of your goodness,the perfect seal of your 

likeness—revealing you, the Father, in himself—living Word, 

true God, Wisdom before the ages,Life, 

Sanctification, Power, and the true Light. 

(Anaphora of the Liturgy of Saint Basil the Great)

85. God the Father begets the Son in freedom and love. The invisible love of the Father, from which the Son is begotten, becomes visible in the Son: “The Father is the invisible [Revelation] of the Son, and the Son is the visible [Revelation] of the Father.”(Irenaeus of Lyons, Against Heresies, IV, 6, 6) In this love, the Father and the  Son  are  one.  The  begotten  Son  is  at  the  same  time  hypostatically  (as Person) different from the Father. The Father begets Someone other than himself, revealing himself completely within the Son, as Other.(See Athanasius the Great, First Letter to Serapion, 16)
86. The Son of God is a reflection of “God’s glory and the exact imprint of God’s very being” (Heb 1:3). His personal generation from the Father is a begetting of “Light from Light, true God from true God.” The Son of God, “reveals in himself the Father.” He is the “living Word,”(Liturgicon, The Divine Liturgy of our Holy Father Basil the Great, Anaphora) who was in God “from all ages” and was God (see Jn 1:1). This Son of God is “the image of [the Father’s] goodness, the perfect seal of [the Father’s] likeness,”(Liturgicon, The Divine Liturgy of our Holy Father Basil the Great, Anaphora) “the image of the invisible God” (Col 1:15). Therefore, the Son of God is simultaneously the Word and Image of God.

From Christ Our Pascha, 

the Catechism of the Ukrainian Catholic Church