What charcoal does to coals and what wood does to fire can be stated clearly. Alternate translation: "As charcoal helps coals burn and as wood helps fire burn" (See: [[rc://en/ta/man/translate/figs-explicit]])
To kindle something means to set it on fire. Setting strife on fire is a metaphor for causing people to fight or argue. Alternate translation: "causing people to fight" or "causing people to argue" (See: [[rc://en/ta/man/translate/figs-metaphor]])