God the Son has been seen in various ways (anthropomorphic visions, angelic visits) in sundry times in the Old Testament. 

In the New Testament, a specific divine person (the Word was God and only begotten God) became human (the Word became flesh) and was named "Jesus". Jesus Christ was the One who came from God (the Father) via eternal generation that's why He alone had seen the Father (cf. John 1:1, 1:14,  6:46). Here the vision of God the Father was said to be experienced by Christ alone due to his relationship with the Father as his [the Father's] only begotten. This is understandable because Jesus was the pre-incarnate Word (Greek: λογος, the word or self-reflection of God). God the Father sees himself through his own Son who is his true image and likeness in eternity. The Son sees his Father who eternally begets him and the Son personally knows him due to their unity in one nature. *Also, **the Son** does whatever he **sees the Father** is doing (John 5:19).* Here the action of the Father is being imitated by the only begotten who sees exactly what his Father is doing and this relationship shows the Son is omnipotent and of the same nature with the Father whom he can see and imitate. John 1:3 tells us that Jesus Christ in his pre incarnate state was *through whom all things came into being* which corroborates John 5:19 that the only begotten was omnipotent, doing what he sees the Father is doing and he does them in like manner. 

In the Book of Revelation, Jesus Christ himself sent his message through an angel. Thus, the angel stands in the place Jesus Christ as a representative. This might be the case in the many instances of God appearing to men in the form of a man and was called an angel. It is also noteworthy that the Father is depicted as unseeable in the book of Revelation and that only Jesus was visible (as the Lamb) on the throne of the Father. 

Justin Martyr in the second century C.E. spoke of the angel who appeared to ancient Israel in the form of a man to be the pre incarnate Jesus Christ himself. 

This tradition also had an ancient precedence in pre Christian Judaism particularly in the Qumran community of the Jews who believed in a second Yahweh (another person who is not Yahweh in heaven but has the name of Yahweh in him and that he is identified as the visible Yahweh in the earth) officially known as the Second Power which became a heresy only within Judaism in the latter part of the second century CE. Philo of Alexandria (circa 50 CE) also had this belief and he even called the Logos as the "second God" (σευτεπον θεον).  

On the other hand, God appearing in anthropomorphic visions like in Isaiah 6 was deemed to be the pre-incarnate vision of Jesus Christ himself according to John. Isaiah saw his [Christ's] glory. 

In the Gospels, Jesus Christ himself acknowledged that he was the "one who is like the son of man" in Daniel 7. In the Old Greek, the son of man was described as "coming as the ancient of days" which identified the son of man as the LORD God. If this is the case, Jesus Christ must also be the LORD God who appeared  to Ezekiel in the form of a man (Ezekiel 1:26).