It depends who you ask

The term “Jew” is derived from either Judah or Judaea, I am not sure, but it doesn’t really mat­ter. What mat­ters is how it was used. In the first cen­tury it was used of those who belonged to the reli­gion of the covenant peo­ple. The race is referred to as Israelites, but the reli­gion was Jew­ish. Thus, Paul can argue that those who were of the faith of Abra­ham were true Jews.

So being Israelite was race, but Jew­ish­ness is a reli­gion, just like Chris­t­ian. For this rea­son refer­ring to an Israelite con­verted to Chris­tian­ity as “Jew­ish Chris­t­ian” is a con­tra­dic­tion, and is deeply offen­sive to Jews. The same way we don’t call those Mus­lims who con­verted to Chris­tian­ity as “Mus­lim Christians”.

What you need to realise is that in the first cen­tury the Jesus move­ment was a reform branch of Judaism. Their Israelite mem­bers con­tin­ued to attend syn­a­gogue meet­ings and par­tic­i­pate in the Tem­ple ser­vices. When Jacob (i.e. James) the Just was killed, four Phar­isees died along his side, he was held in such a high respect.

Not long after the destruc­tion of the Tem­ple and the fail­ure of the Bar-Kohba revolt the Gen­tile Church quickly departed from her Jew­ish roots and rapidly adopted Greek philo­soph­i­cal ideas dur­ing the very tur­bu­lent sec­ond cen­tury, which ideas later on became fixed. Ergo, Chris­t­ian the­ol­ogy does not the slight­est resem­ble the the­ol­ogy of Jesus and the apostles.

Chris­tians read their bibles through the veil of tra­di­tion that is block­ing their sight. If you try to remove it they get offended, for it feels secure to have the veil. The ques­tion is this: Does truth mat­ter? Espe­cially, when one’s des­tiny is hor­ri­bly effected.

Today the term is often used of the race.

No, Abra­ham was not Jew­ish in the sense of the orig­i­nal­ity of the term. How­ever, he was of the very same reli­gion we are called to fol­low, and in the first cen­tury that reli­gion was referred to as Jewish.