How do we choose which biblical laws to follow?
If you “choose” which part of the bible to follow and which part to ignore, then you are putting yourself in an authority position above the Word written therein,
and you might as well not bother with the bible at all at that point, because YOU are the authority, self defined, above that authority of the standard therein written.
Now, if this is an OT vs NT objection, the OT is interpreted in light of the NT. Case closed.
We don’t. The Bible as a whole makes it clear how one is to live.
Besides, have you not read where Jesus says there are only two commandments? Do you think following two commandments requires a lot of picking and choosing among rules?