1. Peter is Given the keys. Matt. 16:19 Very clear Jesus is speaking Only to Peter Here. He will later Give Keys to the other disciples. Matt.18:18 Keys are authority, decision making power. Isa. 22:22 and can be passed down to other people. Making him the Head of the Church and the Official Representative of God on Earth.
2. Solomon (Man) is Called the "Son of God" the official Representative of God on earth, In the O.T.
a. Solomon is promised blessing for choosing wisdom over revenge and greed.
b. Solomon is involved in trade (buying & selling) in which he receives 666 (1 Kgs 10.14 / 2 Chr 9.13) talents of Gold in tribute each year.
c. Solomon violated Gods commandments misrepresenting God by making an alliance with the King of Egypt (Worldly Government)
d. Solomon violated Gods commandments misrepresenting God by marrying foreign wives and worshiping God in a wrong way.
e. Solomon violated Gods commandments misrepresenting God by enslaving and abusing God's people
3. Beast Rev 13.18 Identified with 666. The beast is identified with Solomon, Gods Representative.
4. God's Representative is the Church the Holder of the Keys. The Roman Catholic Church.
Did the Roman Catholic Church while in a Church/State Alliance
a. misrepresent God in any way? Yes
b. increase it wealth by slave trade Yes.
c. enslave people? Yes
d. did they change God's law according to Daniel 7? yes they got rid of the command against Idols and they claim to have changed the holiness of the Sabbath to Sunday by Sylvester I at the time of Constantine. NOTE . The claim that the Lord's day is pagan is wrong. The claim that the Lord's Day Replaced the Sabbath is wrong. The Lord's day was an additional festival to the Sabbath worship in the Synagogue. They did both. It is based on Palm Sunday, Easter Sunday and Pentacost Sunday. The Lord's day was created by Paul, Apollos, Prycilia & Aquilla in Ephesus in order stop conflict with the Jews, teach Christ and create a separate identity from the Synagogue so outsiders could tell the difference between Jew and Christian.
5 . Did they Misrepresent God to the people.
a. Yes they command people to not marry as the highest form of dedication to God. Nuns and Priest. The proper representation of God is in relationships is the Mother/Father model the 'Image of God on Earth.
b. They teach God will burn you and torture you forever if you don't accept him, instead of cremation. Malachi 4:3
c. They teach Evolution rather then Creation
d. They teach poverty as a virtue and the highest form of spirituality. Rather then God wanting to prosper us "be Fruitful and Multiply".
e. They teach the prophecy are either in the past or in the future but not on going. Changing the Times (prophecy) Daniel 7
6. When did Sunday usurp the Sabbath? When the became allied with the State at the time of Constantine.
7. When was the Sabbath banned? At the time of the Pagan resurgence by Julian the Apostate. The church is now allied with the government and in order to avoid state persecution of Christians by the pagan state they hid out in the synagogue. That is why the Sabbath was banned. for political reason not spiritual reasons.
So yes Sunday can be the Mark of the Beast if it is associated with a wrong political and theological adjenda. 666 in the OT is only connected to God's People 1 Kgs 10.14 / 2 Chr 9.13, Ezra 2:13. So it can only be God's people.