wiped android OS accedentely in twrp in sm-j700h/ds
Have you tried marking also the NAND ERASE option in Odin? Although marking the nand erase option would wipe the whole phone including the twrp and everything...and then try reflashing by going into download mode on your phone and then to Odin, you'll see a green/blue mark on the ICOM or something like that. If you pass on flashing and it gets stuck on bootloop, don't panic, just restart the phone and boot into recovery mode and wipe/reset user data! That should do it c:

There's also another thing you can do, you can extract the .tar.md5 using this guide
There you can find the system.img file and from there, you can flash the system.img using fastboot, needless to say that you must have your bootloader unlocked!

You could also try Samsung kies/smart switch, whichever suits you c: