Pentecost

 On the very first Pentecost (Shavuot/Festival of Weeks), God made a covenant with the Jewish people. This covenant was the Covenant of the Law. (The Law of Moses). It is 613 commandments, summarized by the 10 Commandments.

This Covenant was a marriage covenant. God became husband to the Jewish people. (Exodus 19:5-8)  As a wife says "I do" when uniting in marriage with her husband, so the Jewish people said, "We will do" in Exodus 19:8 when they united in marriage with God by their promise to obey God's Law. (Jeremiah 31:31-34, Jeremiah 3:14, Isaiah 54:5).

The Apostle Paul explained how God made a way of escape for His people the Jews out of their binding covenant of the Law, for the Law brought death. (Romans 8:2). "Know ye not, brethren, (for I speak to them that know the law,) how that the law hath dominion over a man as long as he liveth? For the woman which hath an husband is bound by the law to her husband so long as he liveth; but if the husband be dead, she is loosed from the law of her husband." - Romans 7:1-2 KJV 

The way that God would release His people from their marriage to Him and the binding covenant of the Law was for Him to die. But how could God die??  While the Spirit of God cannot die, the flesh that God manifested Himself in could die. This flesh and blood body of God is called the Son of God. Thus, to release His people from their marriage covenant of the Law,  God manifested Himself in flesh, born of a woman, and died on the cross. God released His people from their marriage covenant with Him by the death, burial, and resurrection of the flesh He manifested Himself in.

Paul continues his explanation:

“So then if, while her husband liveth, she be married to another man, she shall be called an adulteress: but if her husband be dead, she is free from that law; so that she is no adulteress, though she be married to another man." - Romans 7:3 KJV

Christ, God manifest in flesh, was born to die for His wife. (Acts 20:28, Ephesians 5:25-27, 31-32).

The Jewish people become God’s wife once again through His new covenant, which also began on the Day of Pentecost. (Shavuot). God released the Jewish people from their covenant of the Law so they could enter into His new covenant of grace by repentance, baptism in the name of Jesus for the remission of sins, and receiving the gift of the Holy Ghost. (Acts 2:38-39, John 3:29-30, 2Corinthians 11:2).

"Wherefore, my brethren, ye also are become dead to the law by the body of Christ; that ye should be married to another, even to him who is raised from the dead, that we should bring forth fruit [new converts] unto God." - Romans 7:4 KJV

The Jewish people became free so they could enter the New Covenant of grace by marriage to their very own husband that now brought them grace, Jesus Christ - God manifest in the flesh - that rose from the dead. (John 1:17)