Wiped System Partition... No OS.. How can I recover it back?
Download the following file (J730GMTCE2AQJ1_TCE) from samfirmware.com: direct link
Extract (unzip) the firmware file
Download Odin v3.12.7
Open Odin v3.12.7 (make sure to Run as administrator)
Reboot your SAMSUNG J7 PRO (SM-J730GM) into Download Mode (press and hold Home + Power + Volume Down buttons)
Connect phone and wait until you get a blue sign in Odin
Add the firmware file to AP / PDA
Make sure re-partition is NOT ticked
Click the start button, sit back and wait few minutes for it to install the stock operating system.


Instructions source (personally tested on another Samsung device)