1)
What is the significance of "Pecham l'Gechalim v'Etzim l'Esh"?
1.
Rashi: Coals of fire ignite glimmering coals. Wood ignites a fire. So an Ish Madon widens a feud.
2.
Malbim: Pecham (sparks) suffices to ignite coals of fire. To ignite a fire, wood is needed; sparks do not suffice. Lecharchar (to arouse) a feud, Ish Madon suffices - he arouses the need to go for judgment. This is like a flame and coal, to make the feud burn.
3.
Malbim (according to Mashal): This corresponds to one who complains about Hashem's Midos; he is Ish Madon. Also refer to 26:22:2:4.
2)
What is "Lecharchar"?
1.
Metzudas Tziyon: It is to ignite the flame of quarrel.