Though man failed in each earlier dispensation, none of the dispensations prior to this present "dispensation of the grace of God" (Eph 3:2) should be considered a failure of God. God is eternally all knowing! He foreknew man's hopelessness and so prepared "from the foundation (beginning) of the world," by making provision of "the Lamb of God," Jesus Christ, to die for the sins of all mankind.  The previous failing dispensations are so man can see that nothing else works ... except for man to receive of God's 'free gift' of salvation in Christ, which the Bible calls GRACE.

Rev. 13:8 … the Lamb slain (already) from the foundation (beginning) of the world. 

2 Cor. 5:19 God Was In Christ, Reconciling The World Unto Himself, Not Imputing their Trespasses (Sins) unto them;

Christ gave Paul "the gospel of the grace of God" (Act 20:24) applying to us in this age of grace.

The past failed dispensational relationships we've examined earlier…  were to demonstrate to Man his utter hopelessness... apart from God's intervention... by His Grace.

Man in his innocence, then man under self-rule, then man having God's Promise of a future kingdom, and man having a code of Law-keeping could not make man to Actually be & live Righteously, and God knew this. So God had eternally planned that any man who received His Son would receive His very life. This fuller salvation element comes to mankind by the addition of Christ's very own life,  as "the resurrected Sprit of Life" into man's human spirit. Whosoever would receive Christ as Savior would simultaneously receive Christ's righteous Spirit of life... to live in and through them as their new life.

Romans 3:9-12 … both Jews and Gentiles … are all under sin; 10As it is written, There is None Righteous, no, Not One: 11There is none that understandeth, there is none that seeketh after God. 12They are all gone out of the way, they are together become unprofitable; there is none that doeth good, no, not one.

2 Tim. 1:9 (We) Who (God) hath saved us, and called us with an holy calling, not according to our works, but according to his own purpose and GRACE, which WAS GIVEN US IN CHRIST Jesus before the world began,

John 1:12 But as many as received him, to them gave he power to become the sons of God, even to them that believe on (trust in) his name (Jesus means 'Savior'):

Our only hope for "salvation' and a 'blameless standing' before God is to receive "the Grace of God" expressed in Christ's cross for us... and then also to have His life 'IN US' as the new us. Then we may enjoy the 'peace' of Christ in the close mutual relationship called "the Fellowship of the Mystery."

Ephesians 3:8-10 Unto me (Paul)m less than the least of all saints, is this grace given, that I should preach among the Gentiles the unsearchable riches of Christ; 9 And to make all men see what is The Fellowship Of The Mystery, which from the beginning of the world hath been hid in God, who created all things by Jesus Christ: 10 To the intent that now unto the principalities and powers in heavenly places might be known by the church the manifold wisdom of God,

Ephes. 1:2-5 'Grace' be to you, and peace (rest), from God our Father, and from the Lord Jesus Christ. Blessed be the God and Father of our Lord Jesus Christ, who hath blessed us with all spiritual blessings in heavenly places in Christ: According as he hath chosen us in him before the foundation of the world, (so) That We should (Would) Be Holy and Without Blame Before Him In Love (Our Standing): Having predestinated us unto the adoption of children by Jesus Christ to himself, according to the good pleasure of his will,

Philippians 4:7 And the peace of God, which passeth all understanding, shall keep your hearts and minds through Christ Jesus.

As Christians today, We Stand Righteous By His Pure Grace… Not at all By our Good Works

Romans 11:6 And if by grace (100%), then is it NO (0%) More of Works: otherwise grace is no more grace. But if it be of works (even 1%), then is it no more grace: otherwise work is no more work.

Titus 3:5 Not by works of righteousness which we have done, but according to his mercy he saved us, by the washing of regeneration, and renewing of (Gk. ek, from and with) the Holy Ghost;

In Past Dispensations Israel offered substitutionary animal sacrifices so as a to have their sins Covered and have Right Standing with God. It was by their faith PLUS the sacrifice that their sinful acts were "covered" and they could be counted righteous. (i.e., Abel, Enoch, Noah, Abraham, etc.)

Romans 4:20-22 He (Abraham) staggered not at the promise of God through unbelief; but was strong in Faith, giving glory to God; 21And being fully persuaded that, what he (God) had promised, he (God) was able also to perform. 22And therefore it was Imputed (COUNTED) to him for righteousness.

Romans 4:5 to him that Worketh Not, but Believeth On Him (Jesus Christ) that justifieth the ungodly, his faith is COUNTED for Righteousness.

Dispensations prior to today's "dispensation of the grace of God" (Eph 3:2) offered only a way to 'COVER' MEN'S SINS through their faith PLUS sacrificial offerings… this made No Provision for the evil heart of man... MAN'S Corrupted Heart Life & Nature remained unchanged inwardly!

Jeremiah 17:9 The heart is deceitful above all things, and desperately wicked: who can know it?

Thankfully God knew our heart and our utterly hopeless state, and that we could never meet the righteous standard of "the Law." Knowing this, He made provision for us in doing what we could not do for ourselves. He made it possible for us to be declared righteous by our faith "in Christ" alone.

Galatians 3:21 … for if there had been a law given which could have given life, verily righteousness should have been by the law. <<< But, Only Christ's Life Is Capable of Righteousness.

Ephesians 2:8-9 For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: 9  Not of works, lest any man should boast.

God knew that ONLY Christ's cross and resurrection life operating within man as man's new nature is able to set man free from the power of 'Sin in the flesh' (Rom 8:3b).

Romans 8:2 ... the Spirit of life in Christ Jesus hath made me free from the law of sin and death.

So, the Father's Objective … Was Deeper Than … just 'COVERING MEN'S SINS.' His plan was to literally … Impart CHRIST'S own Eternal Righteous "Spirit of LIFE"…into every believing man's spirit. The believer then is freed from Sin's power and dominion, and then he is capable of actually living Righteously by Christ's Life and Nature.

2 Corinthians 5:21 For he (God) hath made him (Jesus) to be sin for us, who knew no sin (to pay for and take away our sins); (so) that we might be made (AMP, endued with) the (actual) righteousness of God in him (in union with Christ).

Galatians 2:21 I do not frustrate the GRACE of God: for if righteousness (actual, imparted righteousness) come by the law, then Christ is dead in vain

With "the Mystery" of Christ as the Grace & Life of God In Us now revealed to us... we receive His righteous 'Life' with His 'Nature' into our spirit...making us "one spirit" with Him.

2 Tim. 4:22 The Lord Jesus Christ be with thy spirit. Grace be with you. Amen. << "Christ = Grace"

1 Corinthians 6:17 ... he that is joined unto the Lord is one spirit.

Ephes. 3:2-3 … the dispensation (dispensing) of the grace of God (Christ as God's grace) which is given me (to Paul) to  youward (for you): 3How that by Revelation he (Christ) made known unto me the Mystery (of Christ in the believer, Col 1:27, below);

Col. 1:27 … the glory of this mystery among the Gentiles; which is Christ in you, the hope of glory:

2 Peter 1:4 … by these ye might be partakers of the Divine Nature…