Preaching the Gospel, Preparing a People
I would encourage those interested in this topic to consider 1) how iron is actually sharpened, and 2) how is chad/chadad used in other verses. 'Sharpen' is used in a metaphorical sense in all of these determined by it's context: If I said "you are sharp", usually that's meant to be you are smart - but if I said "that was a sharp criticism", that usually is used to mean what you said 'hurt/cut'. Very different. Happy studying!