I switched from a lp gas stove to electric so wanted to close off the lp gas pipe that supplied the stove. I removed the shut off valve that was on the pipe coming out of the wall and wrapped the fitting threads with yellow teflon tape rated for use on gas lines. I tightened up the brass cap and turned on the gas to check for leaks. There was no gas leaking from the cap I put on but there was a leak from the fitting that attached to the pipe coming from the wall.

I initially turned the fitting at the position closest to the wall in the photo below but it spun without any sense of tightening and the gas continued leaking. I then got a second wrench and held the fitting closest to the wall and tightened from the second position from the wall. The leaking sound went away and I got soapy water and lathered all the joints with it and so no sign of bubbling anywhere.

I ordered a gas leak detector from Amazon https://www.amazon.com/Techamor-Y201-Portable-Combustible-Detector/dp/B07BM1XWB8/ref=sr_1_1_sspa?crid=10CGN1XUFQIHY&dchild=1&keywords=gas+leak+detector&qid=1598120176&sprefix=gas+leak+dete%2Caps%2C296&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzOEVFSUpFWVRMT1ZGJmVuY3J5cHRlZElkPUEwNjg4OTg1R0FGNTdJRkVBU0tYJmVuY3J5cHRlZEFkSWQ9QTAwMzE4MjExSVM2VEJVUTRHSjhFJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

and plan to use it as a double check of the pipe fittings.

Just wanted to post to see if there is anything else I can do or could have done differently to make sure the pipe is sealed. Thank you.