In Jesus's time, there were three different sects of Judaism.

One of them, the Sadducees, allegedly believed there was no life after death and that God didn't care at all about what people did or didn't do.

Their answer to your question of following the law is perhaps the most interesting.

They believed that what was put forth as laws were a gift to humanity and that following them inherently led to a better life in the here and now.

While I don't personally see all of the laws put forward as beneficial, there are certainly instances where that makes a lot of sense.

For example, look at the full version of one of the commandments:

Honor your father and your mother, so that your days may be long in the land that the LORD your God is giving you.

• Exodus 20:12

Would following a commandment to take care of your parents in their old age ('honor' here comes from the word for burden) benefit you by setting an example such that when you are old that you too would be taken care of?

This was almost like social security in antiquity, much like the Sabbath was one of the first labor laws preventing working anyone more than 6 days in a row.

There's something called the overjustification effect, where when you introduce external reward systems for something intrinsically rewarding people over focus on the external and forget the internal benefits. I think a number of religions have serious issues with that.

There's even a certain irony in Job, named 'persecuted' in Hebrew because even though he lived a good life he experienced suffering which it explains by the intervention of Satan, today in the most common language among believers being the exact same word as "to do a task with the expectation of a reward."

Maybe we're too focused on the rewards.