Extending lighting cable inside stud wall

[VickyBH]

I am putting up a sound proofing wall and need to extend lighting cables. I have removed the wall lights and connected the joints using Wago connectors for now.

Do I need a box/enclosure to box in wago connectors inside stud wall? The wall lights will be in the same spot, just extending them out to the new soundproofing wall.
Thanks.

 

[endecotp]

The wires in the second photo are a mess. Because they are twisted together, rather than joined with proper terminals, they have got hot and tarnished and damaged the insulation. You should really replace them. One option would be to run a new cable over the surface of the old wall, behind the new insulation.