Yes, this is a good question? Let me first address the issue of God cannot be seen with the physical eyes. John 4:24 states that God by His very nature is a spiritual being. God the Father does not have a physical body. This is stated by Jesus Christ Himself at John 6:46, "Not that any man hath seen the Father, except he who is from God, he hath seen the Father."
What this means is the fact that the Father has no separate manifestation from the Son. The Son is the only manifestation and revelation of the Father. What is known of the Father is revealed through the Son. To see the Son is to see the essence of the Father (John 1:1;18; 10:30; 12:45; Colossians 1:15; Hebrews 1:3).
Now, to the identity of the person who wrestled with Jacob. This is going to require some thinking and knowing your Bible. Yes, Jacob wrestled with this man at Genesis 32:24. Skipping down to vs30, "So Jacob named the place Peniel, for (or because) he said, "I have seen God fact to face, yet my life has been preserved." Jacob claims he saw God.
Now go to Genesis 35:9-15. Vs9, "Then God appeared to Jacob again when he came from Paddanaram, and He blessed him/Jacob." Jumping to vs13, "The God went up from him in the place where He/God had spoken with him."
Going back to Genesis 16:7, we have the first appearance of the angel of the Lord as the angel of the Lord. "Now the angel of the Lord found her/Hagar by a spring of water in the wilderness by the spring on the way to Shur." At vs9, He says I will greatly multiply your descendants so that they shall be too many to count." At vs11 the AOL says to her that she is with child, this would be Ishmael.
Going to vs13 Hagar says, "Then she called the name of the Lord who spoke to her, "Thou are a God who sees; for she said, Have I even remained alive here after seeing Him?" Who else said the same thing at Genesis 33:30?
Genesis 17:1-3, "Now when Abram was ninety-nine years old, the Lord appeared to Abram and said to him, "I am God Almighty; Walk before Me, and be blameless, Vs2, And I will establish My covenant between Me and you, And I will multiply you exceedingly." Vs3, "And Abram fell on his face and God talked with him saying, etc.
This was a physical appearance of the Lord God Almighty and this fact is based on Genesis 17:22, "And when He/God finished talking with him, God went up from Abraham. God also went up from Jacob at Genesis 35:13 after He had spoken to him."
Now for Genesis 18:1-2, "Now the LORD appeared to him/Abraham by the oaks of Mamre, while he was sitting at the tent door in the heat of the day. Vs2, And when he lifted up his eyes and looked, behold, three men were standing opposite him; and when he say them he ran from the tent door to meet them, and bowed himself to the earth. This is an appearance of the AOL and with him were two actual angels. This to was a physical appearance because Abraham offered them bread and water to clean themselves.
The proof that the AOL is the preincarnate Jesus Christ before He incarnated as a man permanently
we have to go to Genesis 22. This is where the Lord ask Abraham to sacrifice his son Isaac. At Genesis 22:11, the AOL calls out from heaven and says, "Abraham, Abraham!" And he said, Here I am." Vs12, He said do not stretch out your hand against the lad, and do nothing to him; for now I know you fear God, since you have not withheld your son, your only son from Me." Genesis 22:15-17, "Then the angel of the Lord called to Abraham a second time from heaven.
Vs16,"By Myself I have sworn, declares the Lord because you have done this thing, and not withheld your son, your only son, vs17, indeed I will greatly bless you and I will greatly multiply your seed as he stars of the heavens, and the sand which is on the seashore; and you seed shall possess the gate of his enemies."
Please notice from vs16 the words "and said." What did the angel of the Lord say? "By Myself I have sworn, declares the Lord etc." For clarification as to the speaker is we will go to Hebrews 6:13-6.
"For WHEN GOD made the promise to Abraham, since He could swear by no one greater, HE SWORE BY HIMSELF, vs14, saying, I will surely bless you, and I will surely multiply you." Vs15, And thus, having patiently waited, he obtained the promise. Vs16, For men swear by one greater than themselves, and with them/men an oath given as confirmation is an end of every dispute."
Now, some say that the angel of the Lord is an actual angel acting on behalf of God Himself and to do His bidding. It is true that the Jews have what is known as "The Law of Agency" which deals with the status of a person (known as the agent) acting by direction of another (the principal), and thereby legally binding the principal in his connection with a third person. The information I just gave is from the Jewish Law of Agency/a Shaliach found in the Jewish Encyclopedia, page 232.
However, from the Jewish Virtual Library the law of agency most if not all of the time deals with, "laws of mamonot (commercial law), or (heave offering), sacrifices, divorce, and betrothal etc. According to the Tosefta (Kid, 4:1), Bet Shammai and Bet Hillel agreed that a person appointed to carry out a specific mandate is disqualified from acting as a witness in a case involving such mandate. The agent/Shaliach is not regarded as the principal as himself since the agent is disqualified from testifying as a witness.
Swear means to state under oath. Swearing an oath is a matter of one's own conscience, therefore Angels cannot swear oaths on behalf of God Himself and Jesus Christ is not an angel but rather the "messenger of the Lord." Angels cannot multiply descendants but the angel of the Lord multiplied Hagars descendants at Genesis 16:10.
The angel of the Lord appeared in the burning bush at Exodus 3:2-6 and claimed to be God at vs6. He appeared to Joshua at Joshua 5:13-15 and said at Joshua 6:2, "And the Lord said to Joshua I have given you Jerico. At Judges 2:1, the angel of the Lord brought you up out of Egypt and led you into the land I HAVE SWORN to your fathers, and said I will never break My covenant."
To be sure, I could give many more references where the angel of the Lord intervened on behalf of Isarael and its people as a mediator. Lastly, there is Malachi 3:1, "Behold, I am going to send My messenger, and he will clear the way before Me, And the LORD whom you seek will suddenly come to His temple; and the messenger of the covenant, in whom you delight, behold, He is coming, says the Lord of hosts." Who do you think this is? Also read Luke 1:68-79. As a side note, the angel of the Lord never appears in the New Testament as the angel of the Lord, although He is mentioned by Stephen at Acts 7.
The Hebrew word for angel is "malak." It means "Messenger, Sent One, Angel. The context determines how it is used. At Malachi 3:1, God says, I am going to send My angel/messenger, and he will clear the way before Me" This is referring to John the Baptist and John is not an angel. Continuing on with the verse, "And the Lord whom you seek, will suddenly come to His temple;" This is the Lord Jesus Christ.
Continuing on. and the malak/angel/messenger of the covenant, in whom you delight, behold, He is coming, says the Lord of hosts." This is referring to "THE" angel of the Lord, the pre-incarnate Jesus Christ who is not an angel but the "messenger" of the Lord in the OT. As a side note, the prophet Malachi, (a human being) well his name is from the word "malak/messenger." Human prophets are messengers as well and are not actual angels.