How did they?

We all know the scriptures are clear ...Jesus is the only way to the father, call upon his name and you shall be saved. We must be born again to enter into the kingdom of heaven.

So my question here is how did the o.t. saints such as David, Abraham, the prophets and such enter heaven?

Jesus said nobody had been to heaven except Him Who came from heaven, meaning Himself.

OT saints expected to go to Sheol, which was considered the holding place of the dead.

That included both the righteous, and the wicked, between which an inseparable gulf existed.

Same way you do...faith. Jesus said Abraham rejoiced to see His day, and saw it and was glad.
To be absent of the body has always meant to be present with the Lord. Salvation has always been by grace through faith. We are fortunate to have a fuller understanding given the completion of scripture. But in the main, nothing has changed.

Ephesians 2:4-7 ~ Because of His great love for us, God, Who is rich in mercy, made us alive with Christ even when we were dead in our trespasses. It is by grace you have been saved! And God raised us up with Christ and seated us with Him in the heavenly realms in Christ Jesus, in order that in the coming ages He might display the surpassing riches of His grace, demonstrated by His kindness to us in Christ Jesus.

Great is the Lord and greatly to be praised!

Habakkuk 2: 4:
Behold, his soul which is lifted up is not upright in him: but the just shall live by his faith.
Gal 3: 6-9:
Even as Abraham believed God, and it was accounted to him for righteousness. Know ye therefore that they which are of faith, the same are the children of Abraham. And the scripture, foreseeing that God would justify the heathen through faith, preached before the gospel unto Abraham, saying, In thee shall all nations be blessed. So then they which be of faith are blessed with faithful Abraham.
Heb 11: 4:
By faith Abel offered unto God a more excellent sacrifice than Cain, by which he obtained witness that he was righteous, God testifying of his gifts: and by it he being dead yet speaketh.
Heb 11: 5:
By faith Enoch was translated that he should not see death; and was not found, because God had translated him: for before his translation he had this testimony, that he pleased God.
Heb 11: 7:
By faith Noah, being warned of God of things not seen as yet, moved with fear, prepared an ark to the saving of his house; by the which he condemned the world, and became heir of the righteousness which is by faith.
Heb 11: 8-9; 11; 13; 37-40:
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. By faith he sojourned in the land of promise, as in a strange country, dwelling in tabernacles with Isaac and Jacob, the heirs with him of the same promise; Through faith also Sara herself received strength to conceive seed, and was delivered of a child when she was past age, because she judged him faithful who had promised; These all died in faith, not having received the promises, but having seen them afar off, and were persuaded of them, and embraced them, and confessed that they were strangers and pilgrims on the earth. They were stoned, they were sawn asunder, were tempted, were slain with the sword: they wandered about in sheepskins and goatskins; being destitute, afflicted, tormented; (Of whom the world was not worthy they wandered in deserts, and in mountains, and in dens and caves of the earth. And these all, having obtained a good report through faith, received not the promise: God having provided some better thing for us, that they without us should not be made perfect.
Heb 9: 13-15:
For if the blood of bulls and of goats, and the ashes of an heifer sprinkling the unclean, sanctifieth to the purifying of the flesh: How much more shall the blood of Christ, who through the eternal Spirit offered himself without spot to God, purge your conscience from dead works to serve the living God? And for this cause he is the mediator of the new testament, that by means of death, for the redemption of the transgressions that were under the first testament, they which are called might receive the promise of eternal inheritance.
Gal 3: 17:
And this I say, that the covenant, that was confirmed before of God in Christ, the law, which was four hundred and thirty years after, cannot disannul, that it should make the promise of none effect.
Gal 3: 22-25:
But the scripture hath concluded all under sin, that the promise by faith of Jesus Christ might be given to them that believe. But before faith came, we were kept under the law, shut up unto the faith which should afterwards be revealed. Wherefore the law was our schoolmaster to bring us unto Christ, that we might be justified by faith. But after that faith is come, we are no longer under a schoolmaster.
Gal 3: 28-29:
There is neither Jew nor Greek, there is neither bond nor free, there is neither male nor female: for ye are all one in Christ Jesus. And if ye be Christ's, then are ye Abraham's seed, and heirs according to the promise.

Before Jesus, the faithful believed in God's promise of eternal inheritance, trusting in the promised Messiah to one day save them. After Jesus, we believe in the Lord's promises and trust in Jesus to save us from the just recompense of our sins.

From the responses of above would that apply to jews today?

Sure, but not as a nation, but as individuals.

By trusting the Word of God and walking in the light they had at the time.

Belief on the coming Savior, Jesus Christ the Messiah, Immanuel for us all, leaving to believe it or not between /God and you and you and me as well as all others too, thank you
Hebrews 11 Faith
F-orever a-ble i-n t-he H-eavens, F-orwarding a-ll i-ssues t-o H-eaven
Trust to God Father in the Messiah, from the first Testament that he was coming.
Now today we here are after that cross, they were there before that cross.
It is the Cross over in his risen life given us to stand in and not quit no matter what troubles happen to us, at least me, and I have been there, as well as could be again. Trusting God, no matter what, been there, have not denied God, do not see to deny God, do see people have and yet changed as Peter did after the resurrection

By believing in God, as He revealed Himself to them - same as today.

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For sure nothing has changed

Jacob wept ---

All his sons and all his daughters rose up to comfort him; but he refused to be comforted, and said, “No, I shall go down to Sheol to my son, mourning.” Thus his father wept for him.

The reason why I ask this question is because I have a dear couple I've known for yrs.
He is Jewish she is christian. Both are wonderful giving people. He is very active in his synagogue.
I just found out that she told my wife she refuses to accept the gospel message if it means her husband would end up in hell
He has never read the new testament but considers Jesus a prophet.
I believe this has been laid at my table to witness to both.
He has helped me with the study and language of the old testament. He studied and lived in Iseral for a few yrs and has a few degrees.
Keeping all things in prayer any advice is much appreciated.

Leastofall.

If one denies the Son, one denies the Father. Remember Jesus' words to the Pharisees. Jews deny Jesus, else they tend to identify themselves as Christian or associated with Jesus. If the Jews (or anyone else) believe in God, let them demonstrate this by believing on the One who He sent - Jesus.

By faith and believing in God's word. Jesus also went and preached to the spirits in prison after his crucifixion to give them the opportunity for salvation, I Pet 3:18-20.