This is my own personal way of studying scripture. The new testament says there is a mystery those in the old testament missed. The new testament is for those that are in Christ, lest why did Jesus Himself give Paul this mystery to reveal to the body of Christ His Church.
The way God dealt with old testament saints is completely different than the way He deals with new testament believers. In the Old testament, the spirit of Satan was commander and chief. That left the soul through which God dealt with them. Their minds, that is why the Law was so important, for where does the Law work? In the mind.
The New Testament Believer has a new Spirit and that is the Spirit of Christ that gives new life, new heart, new mind, the mind of Christ, new birth, by water and spirit, The Water of Life offered to the woman at the well and the Spirit of Christ which is living water. Also we now have the Holy Spirit in us not just with us. Pentecost brought a new mystery, Christ in you the Hope of Glory and the Holy Spirit our teacher of this life.
If I study the old testament, which I do, and I don't see Christ in what I am studying, I have not revealed the mystery of Christ and continue to study and seek the Holy Spirit Teacher to make sure I see Christ in all the old testament as I see Him in the New Testament. Other wise I have missed the truth of the whole Word of God and cannot reconcile the old with the new.
Example: Exodus 26:33 And thou shalt hang up the vail under the taches, that thou mayest bring in thither within the vail the ark of the testimony: and the vail shall divide unto you between the holy place and the most holy.
When was the Vail destroyed? When Christ became the Vail. Now we have access to the Holy of Holies through Him and can come boldly to the Throne of Grace in Christ Jesus who makes us Holy.
This is not a catch all for understanding the old and the new, because of my own mind I miserably lack the capacity to know the things of the Kingdom. I must be born again and trust that He will not give me a stone for the bread of life.
God has made sure that we have all that is necessary to attain His command; "be ye Holy for I am Holy. This Holiness is by the Christ that is in us and He is the Glory of all that God has planned before the foundation of the World. In Christ, Eph 1:4.
What hope do we have of any glory at all?
Colossians 1:27-28 To whom God would make known what is the riches of the glory of this mystery among the Gentiles; which is Christ in you, the hope of glory: Whom we preach, warning every man, and teaching every man in all wisdom; that we may present every man perfect in Christ Jesus:
In Christ: Phillip