Because it was the "Bible" that they read the most and was universally known.
However, let us consider the context of what Paul wrote in say Romans 11:25-26 and what is now the common contextual understanding being written into our translations. The difference is deafening. Paul wrote that,
until, with respect to time, when the 2,300 years of the Gentiles trampling God's Sanctuary and Earthly hosts has run its full course, that after this all of Israel will be saved.
However, below are a number of translations that give a very different context: -
Rom 11:25-26: - 25 For I do not want you to be ignorant of this mystery, brothers and sisters, so that you may not be conceited: A partial hardening has happened to Israel
until the full number of the Gentiles has come in.
26 And so all Israel will be saved, as it is written:
(from
The NET Bible®, Copyright © 1996-2006 by Biblical Studies Press, L.L.C., Dallas, Texas,
www.bible.org. All rights reserved. Used by permission.)
Rom 11:25-26: - 25 I want you to understand this mystery, dear brothers and sisters, so that you will not feel proud about yourselves. Some of the people of Israel have hard hearts, but this will last only
until the full number of Gentiles comes to Christ.
26 And so all Israel will be saved. As the Scriptures say,
Holy Bible,
New Living Translation ®, copyright © 1996, 2004 by Tyndale Charitable Trust. Used by permission of Tyndale House Publishers. All rights reserved.
Rom 11:25-26: - 25 I want you to know about this truth from God, dear brothers, so that you will not feel proud and start bragging. Yes, it is true that some of the Jews have set themselves against the Gospel now,
but this will last only until all of you Gentiles have come to Christ-those of you who will. 26 And then all Israel will be saved.
TLB
Today we have so many variation, because some person/committee disagreed with another translation.
Oh well, today there are many stiff necked people who have a very different understanding of the Context to what God lead the writers of the Bible, i.e. the OT and the NT, to pen.