I have two seperate circuits, one for four recessed lights and another
for a chandelier lift. I thought I needed more power for expansion but
has turned out not to be the case. I no longer need these two circuits
to be seperate and would like to combine them into one. I have ran out
of room in my panel and was wondering if I could combine these two
circuits by putting the two wires into one circuit breaker? Or, should
I use a junction box two combine the two lines and a cable from the
panel to feed the junction box?

Is there advantage to using one method over another? Or, is it even
permitted to combine two circuits at a circuit breaker?

Thanks.