1) God has identified these men and women as “our fathers”  (1 Corinthians 10:1). That Paul says this to the Corinthians is especially significant since they are characterized as ‘Gentile’ or non-Jewish Christians (1 Corinthians 12:2).
2) Therefore, though it would be a sin for us to try to live in the past (Hebrews 10:1ff.), it would also be a sin for us to forget the past (1 Corinthians 10:6 & Romans 15:4).
3) Indeed God would not only have us not be ignorant of what He did through these saints, but also of what He did through them for us (Acts 3:25). This is not to deny the unique, mediatorial work of Christ but rather to appreciate that our mediator himself came through the genealogy and line of these men and women, thus sanctifying their faith.
4) As such, these are not merely stories to read but the root from which we, the branch, come (Romans 11:15ff.). Though we participate in the life of Christ, they too participated in it and thus anticipated His life in their own.
5) That a study of the lives of the Old Testament saints not only includes the testimony of faith but the examples of their faith is seen in Hebrews 11 in its entirety. Note especially vs. 8: “By faith Abraham, when he was called to go out into a place which he should after receive for an inheritance, obeyed; and he went out, not knowing whither he went” (emphasis mine).
6) Old Testament apostates and rogues are used by New Testament authors to illustrate the dangers of sin and corruption to the churches (2 Peter 2:15; Jude 11; Revelation 2:20)
7) James writes: “But whoso looketh into the perfect law of liberty, and continueth [therein], he being not a forgetful hearer, but a doer of the work, this man shall be blessed in his deed.” (James 1:25) Those who have known the law in the past and have walked in it are the believers scribes & lawyers, pointing them to its meaning and importance through their living faith and application of its teaching (see, for example, what God says about Abraham in Genesis 26:5).
8) It is reasonable to conclude that since one of the great gospel promises is sanctification itself (Hebrews 8:11), that the Old Testament would hold out many examples of those who were sanctified.
9) The Old Testament saints are called a “great cloud of witnesses” (Hebrews 12:1). Though the greater part of their witness was a foreshadowing of the work of Christ (Hebrews 12:2-3), this does not discount their witness to righteousness or righteous living, as vs. 1 goes on to explain in the command to “lay aside every weight, and the sin which doth so easily beset us.” Indeed, various Old Testament saints are held out to us an example of righteousness (e.g. 2 Peter 2:5-8).
10) This is demonstrated when we observe that so much of the content of the New Testament (besides the gospels & Acts) are epistles: written instruction and doctrine but the examples are somewhat lacking.
11) It may be contested that since the Saviour has come, one need only follow the life of Christ which is sufficient for this present age. In reply, consider the following:
a) This is contradicted by Christ’s own words (Matthew 12:3ff, 16:24; Luke 6:23, 17:32)
b) This is contradicted by Christ’s own example, as one who obeyed the law and did not disobey as many of the physical seed of Abraham had. See Matthew 2:15 (cf. Matthew 3:17 & 17:5).
c) This is contradicted by the New Testament epistles which, having been written after the close of Christ’s earthly ministry, still urge us to look to those who were living before the cross as godly examples (see, particularly, the points above and 2 Timothy 3:16 in general).
12) It may be contested that such a reading of the Old Testament will inevitably lead to legalism & moralism. In response, consider the following:
a) One might accuse many of the New Testament authors the same due to the instructions they impart to the saints (1 Corinthians 6:9-10; 2 Peter 1ff.; 1 John 3:1ff.).
b) Though legalism & moralism lurk whenever obedience is preached, so do antinomianism and unrighteousness whenever the gospel is preached (Romans 6:1ff.). Should we then not preach the gospel? God forbid.
c) This would only be true if our approach to the Old Testament diminishes or ignores the Christ centered hermeneutic of our Lord and His disciples (Luke 24:44 & 2 Corinthians 1:20).
d) Surely our Lord Himself, who not only steers us from the danger of legalism, can steer us from the danger of moralism if we entrust our scripture meditation to Him and seek His blessing in it.
13) Finally, it is beneficial to consider why this approach to the Old Testament is of such importance and thus why it should be maintained:
a) Consider that most of these scriptural biographies are written down after these events transpired and generations have passed. Though God verbally confirmed to Isaac and Jacob the promises made with their forefather Abraham, these were only written down at the time of Moses. Even then, the gospel promise had been unfulfilled for Christ had not yet come. So as we read about the lives of the Old Testament saints we can be assured that they have application for us precisely because they have been passed on. This brings to mind Paul’s statement that these things were written “for our learning” (Romans 15:4 –emphasis mine).
b) We must understand that though the Bible is not complete or finished without the New Testament canon, neither is it whole without the Old Testament canon. For example, if a portion of one’s inheritance is withheld because it may only be handed over at the age of maturity due to what is being received (such as an estate or a vehicle), we would not conclude that the entire inheritance is now rendered meaningless. But, if after reaching maturity the inheritor discovers that he has been robbed of part of his promised possession (say some riches set aside to maintain himself that had been previously been pilfered), then we would conclude that the inheritance has, at least in part, been rendered void and the inheritor bereft of the full blessings intended for him. Unless we believe that the new covenant completely supplants everything the Old Testament teaches, there is value in it today and indeed, a great loss to us, if we do not receive it as the Word of God for us today.