REVELATION TO THE GREAT MYSTERY IN THE BIBLE The New Testament talks about a Mystery existing for ages and reveals the mystery. Let us also see some of the mysteries that existed over ages.

MYSTERY - REVEALED
The New Testament talks about the Mystery in many verses and finally reveals it in 1 Tim 3:16.
Col 1:26 The mystery which has been hidden from ages and from generations, but now has been revealed to His saints.
1 Cor 2:7 we speak the wisdom of God in a mystery, the hidden wisdom which God ordained before the ages for our glory,
Rom 16:25 God establishes us according to the gospel the preachings of Jesus Christ, according to the revelation of the mystery kept secret since the world began
Eph 3:3 by revelation He made known to me the mystery (as I have briefly written already, 4 by which, when you read, you may understand my knowledge in the mystery of Christ), 9 and to make all see what is the fellowship of the mystery, which from the beginning of the ages has been hidden in God who created all things through Jesus Christ;
1 Tim 3:16 Without controversy great is the mystery of godliness:-
God was manifested in the flesh,
Justified in the Spirit,
Seen by angels,
Preached among the Gentiles,
Believed on in the world,
Received up in glory. (Ref Mark 4:11 / Rom 11:25 / Eph 5:32;6:19)

MYSTERIES
The Old Testament has some mysteries, pointing to a particular person in different situations relating to God.

Mystery: Gen 2:24 For this reason a man will leave his father and mother and be united to his wife, and the two will become one flesh.(Eph 5:31)
Revelation: Eph 5:32 This is a profound mystery, but I am talking about Christ and the church.

Mystery: Gen 3:15 I will put enmity Between you and the woman, And between your seed and her Seed;
Revelation: Gal 3:16 to Abraham and his Seed were the promises made. He does not say, And to seeds, as of many, but as of one...who is Christ.
(Mark 4:14 & Luke 8:11 - The Seed is the Word of God)

The Angel of the Lord first doesnt appear to Abraham, Moses, Noah, Enoch or any other man of God. But He appears to an egyptian, a woman, slave, a concubine, who is despised and rejected. He has a heart for the weak, the meak, the gentile. We also see that he has a powerfull authority to give great blessings that is more of a Gods ability. The Angel of God only appears in the old testament. He is refered to as God, Lord, Angel of God, Angel of the Lord, Commander of the Army of Israel, a Man, an Angel with a sword. In many of the verses more than one of these names are used at the same situation as below:-

NOTE (added Feb 24 09) :- Kindly revisit this article in March, since this article is still incomplete and in process of research...

Mystery: Gen 16:7 the Angel of the LORD found her by a spring of water in the wilderness, (blesses her son Ishmael, the founding father of the Ishmaelites.)
Gen 22:10,11-15 Angel of the Lord stops Abraham from sacrificing Issac.
Revelation: Gen 21:17 God heard the voice of Ishmael and the Angel of the Lord spoke to hagar from Heaven...
Gen 31:11 the Angel of God spoke to Jacob 13 I am the God of Bethel, where you anointed the pillar and where you made a vow to Me.
Exo 3:2 the Angel of the LORD appeared to him in a flame of fire from the midst of a bush... 4 So when the LORD saw that he turned aside to look, God called him.
Exo 14:19 the Angel of God, who went before the camp of Israel... 24 The Lord looked down from heaven and troubled the army of Eqypt.
Judg 2:1 the Angel of the LORD said: “I led you up from Egypt and brought you to the land of which I swore to your fathers; and I said, ‘I will never break My covenant with you.

Mystery: Gen 18:1 Then the LORD appeared to him by the terebinth trees 2 three men were standing by him; 10 And He said, “I will certainly return to you according to the time of life, and behold, Sarah your wife shall have a son.”...22 Then the men turned away from there and went toward Sodom, but Abraham still stood before the LORD (since He had the authority to destroy.
Revelation: Who could this Lord be, Jesus is the only Lord who appears with 2 other angels.
Gen 21:1 the LORD visited Sarah as He had said, and the LORD did for Sarah as He had spoken. 2 For Sarah conceived and bore Abraham a son in his old age, at the set time of which God had spoken to him.
Act 1 (Jesus returns with 2 angels, after He rose)
Luke 24:3 Then they went in and did not find the body of the Lord Jesus. 4 And it happened, as they were greatly perplexed about this, that behold, two men stood by them in shining garments.

Mystery: Gen 32:26 Jacob fights the Lord and asks His name 28 Your Name shall no longer be called Jacob but Israel 29 “Why is it that you ask about My name? 30 Jacob called the name of the place Peniel: “For I have seen God face to face, and my life is preserved.”
Revelation: Judg 13:8 Manoah prayed to the LORD, and said, “O my Lord, please let the Man of God whom You sent come to us again and teach us what we shall do for the child who will be born.” 9 And God listened to the voice of Manoah, and the Angel of God came to the woman again ... 11 So Manoah arose and followed his wife. When he came to the Man, he said to Him, “Are You the Man who spoke to this woman?” And He said, “I am.”...17 Then Manoah said to the Angel of the LORD, “What is Your name, that when Your words come to pass we may honor You?” 18 And the Angel of the LORD said to him, “Why do you ask My name, seeing it is wonderful?
Isa 9:6 For unto us a Child is born, Unto us a Son is given; And the government will be upon His shoulder. And His name will be called Wonderful, Counselor, Mighty God, Everlasting Father, Prince of Peace.

Mystery: Exo 4:24 it came to pass on the way, at the encampment, that the LORD met him and sought to kill him.
Revelation: Num 22:22 God’s anger was aroused because he went, and the Angel of the LORD took His stand in the way as an adversary against him...with His drawn sword in His hand, ... 31 Then the LORD opened Balaam’s eyes, and he saw the Angel of the LORD standing in the way with His drawn sword in His hand;
Mat 10:34 Jesus came with a sword.
Eph 6:17 the helmet of salvation, and the sword of the Spirit, is the word of God;
Heb 4:12 the word of God is living and powerful, and sharper than any two-edged sword

Mystery: Josh 5:13 when Joshua was by Jericho, a Man stood opposite him with His sword drawn in His hand. 14 He said, “as Commander of the army of the LORD I have now come.” And Joshua fell on his face to the earth and worshiped, 15 Then the Commander of the LORD’s army said to Joshua, “Take your sandal off your foot, for the place where you stand is holy.”
Revelation: Exo 3:5 God said, “Do not draw near this place. Take your sandals off your feet, for the place where you stand is holy ground.” 6 “I am the God of your father—the God of Abraham, the God of Isaac, and the God of Jacob.” And Moses hid his face, for he was afraid to look upon God. 7 And the LORD said:

Mystery: Jud 6:11 the Angel of the LORD came and sat under the terebinth tree 12 And the Angel of the LORD appeared to him, and said to him, “The LORD is with you, you mighty man of valor!”...14 Then the LORD turned to him and said... 23 Then the LORD said to him, “Peace be with you; do not fear, you shall not die.” 24 So Gideon built an altar there to the LORD, and called it The-LORD-Is-Peace.
Revelation: Isaiah 9:6 For unto us a Child is born, Unto us a Son is given; And the government will be upon His shoulder. And His name will be called Wonderful, Counselor, Mighty God, Everlasting Father, Prince of Peace.
John 14:27 Jesus: Peace I leave with you, My peace I give to you; not as the world gives do I give to you.

Mystery: Dan 3:25 I see four men loose, walking in the midst of the fire; and they are not hurt, and the form of the fourth is like the Son of God.
Revelation: Matt 15:15 Jesus asked Peter, "who do you say that I am?" 16 Simon Peter answered "You are the Christ, the Son of the living God."

Conclusion:- The Mystery over the ages is about God manifesting in the form of a human as Jesus Christ. (1 Tim 3:16)