2,500 years ago, Jews were slaughtering goats and offering them as burnt offerings on altars in order to absolve themselves of sin.
Modern Judaism is distinctly different than what was practiced two millenia ago.
Modern Judaism is distinctly different than what was practiced two millenia ago.
The reason it's not practiced today is 'just' because the decree also states that you have to perform the sacrifice at the great temple on temple mount. That poses a technical problem, since: 1. The temple was destroyed 2k years back, and there's a pretty famous mosque standing in its place. 2. Religious jews have to do a special kind of purification in order to even be on temple mount, and this purification is impossible at the moment, again for weird technical reasons (they need a red cow, don't ask).
BUT, if there was a temple, and there was a purification rite, religious jews would, in all likelihood, be happily burning offerings 3 times each year.
In short, not as different as you may think.
There is a priestly caste, the kohanim. The kohanim have various obligations and duties, most of which are moot in the modern world, and one of which involves the hand gesture made famous by Leonard Nimoy.
There is another caste, the Levites, but they have no remaining duties.
Firstly your now considering early Judaism unenlightened. However the core beliefs are still very much the same; and many customs from contemporary Norse times are still observed by some sects.
Secondly that's the practice of religion; which is very different from a belief itself. It is possible to believe in God or a set of gods without following the practices of the organisations themselves. The difference between then and now is that a) you were "sold" the practices as an inherent part of belief in XYZ God and b) to believe without practising them was dangerous. As a result the actual belief in the Abrahamic God is somewhat irrelevant to the practices.