Rev 3:9 Indeed I will make those of the synagogue of Satan, who say they are Jews and are not, but lie—indeed I will make them come and worship before your feet, and to know that I have loved you.
Why did God called this Jewish synagogue the synagogue of Satan.
Deu 16:16 "Three times a year all your males shall appear before the Lord your God in the place which He chooses: at the Feast of Unleavened Bread, at the Feast of Weeks, and at the Feast of Tabernacles; and they shall not appear before the Lord empty-handed.
After Moses had taken the Israelites out of Egypt, God made the covenant with them by giving them the Mosiac Law. In this law Yahweh would be their God and they would become His people. He would dwell amongst them in the place that He had chosen. Three times a year they must appear before Him in the place He had chosen.
God chosen Places
During their pilgrimage in the wilderness and the conquest of Canaan Land, God chose to dwell in the Tabernacle built to His specification. After King Solomon had built the temple of God to His specification, then God replaced and obsoleted the Tabernacle by moving into the new temple of God. In 70AD, the temple of God was razed to the ground thus ending Judaism.
The death of our Lord Jesus, ended Judaism by tearing the temple's veil into two. After the resurrection of our Lord, every born again Christian was given the Holy Spirit, therefore his physical body becomes the temple of God thereby replacing the temple in Jerusalem.
John 20:21-22 So Jesus said to them again, "Peace to you! As the Father has sent Me, I also send you." And when He had said this, He breathed on them, and said to them, "Receive the Holy Spirit."
Building of the Temple of God
Exo 25:8-9 And let them make Me a sanctuary, that I may dwell among them. According to all that I show you, that is, the pattern of the tabernacle and the pattern of all its furnishings, just so you shall make it.
The tabernacle and all its furnishings must be built in accordance to the design given by God. The priest's clothings, preparation, services and even sacrifices must be offered as commanded. God will not accept any flaw or mistake in the preparation of His temple nor any sinful worshipper.
Isa 1:13-15 "Bring no more futile sacrifices; Incense is an abomination to Me. The New Moons, the Sabbaths, and the calling of assemblies— I cannot endure iniquity and the sacred meeting. Your New Moons and your appointed feasts My soul hates; they are a trouble to Me, I am weary of bearing them. When you spread out your hands, I will hide My eyes from you; even though you make many prayers, I will not hear. Your hands are full of blood."
Synagogue of Satan
Deu 5:32-33a "Therefore you shall be careful to do as the Lord your God has commanded you; you shall not turn aside to the right hand or to the left. You shall walk in all the ways which the Lord your God has commanded you,"
Only the Priesthood could perform all the religious functions for sacrifices, worship, celebrations and feasts in the temple of God in Jerusalem.
Synagogues were set up for the teaching of the Law by scribes and Pharisees.
An abomination to celebrate any Jewish feast without the Temple
Any Jewish feast, sacrifice, offering, worship and celebration held in synagogues, churches, gatherings, meetings or fellowships is an abomination to the Lord, for our Father God condemns such lawlessness as 'synagogues of Satan'