Abraham is regarded as a very righteous person by Judaism, Christianity and Islam. We find evidence of his righteousness in the Old Testament, the New Testament and in the Qur'an. Some of the references mentioning this are:

And the Lord had said unto Abraham…… I will make of thee a great nation; and I will bless thee, and make thy name great; and thou shalt be a blessing. And I will bless them that bless thee; and curse him that curseth thee; and in thee shall all families of the earth be blessed. (Gen.12:2-3)

In the New Testament we find the following:
And it came to pass, that the beggar died, and was carried by the angels into Abraham's bosom. (Lk.16:22)

The blessed dead were with Abraham, they were conscious and were comforted. (Lk.16:25)

Allah tells us in the Qur'an, the following about Father Abraham:

Abraham was indeed a model; devoutly obedient to Allah; true in faith; and he joined not gods with Allah. He showed his gratitude for the favours of Allah who chose him, and guided him to a Straight Path. And We gave him good in this world and he will be in the Hereafter in the ranks of the Righteous. So We have taught thee: Follow the ways of Abraham, the true in faith. (16:120-123)

It means that because he followed the law and was grateful for Allah's mercies and blessings on him, he is in Paradise among the ranks of the righteous.

If I follow the law of  God, as Abraham did, and I don't ascribe a partner with the Lord, I shall be considered to be righteous. I will not only be following the ways of Father Abraham, but will also be upholding the teachings of Moses and Jesus.

Never forget that Jesus said:

Think not that I am come to destroy the law or the Prophets; I am not come to destroy, but to fulfil. (Mt. 5:17)

Even Paul said:

I had not known sin but by the law. (Rom.7:7)

What Abraham taught us is that we need to believe that there is only one Creator of the universe called the God of Abraham, and that we need to abide by the law that God give to us and we shall be righteous.

If we do both these things, then we are automatically saved. As a result we do not need a Saviour, like Jesus to take us to Paradise. We can save our selves.

Allah tells us about this in the Qur'an in the following verse; Believe and do good.