‘ So the near kinsman said to Boaz, “Buy it for yourself.” And he drew off his shoe.'
Ruth 4:7 explains why the near kinsman did what he did. He devolved on Boaz the right to act as kinsman redeemer and demonstrated the fact in front of witnesses by taking off his shoe, and no doubt handing it to Boaz. We are not told how much it was at that stage seen as an act of shame, as opposed to being just evidence of the transaction (Deuteronomy 25:9-10). But it does bring out that the law of Levirate marriage was still seen as being of great importance (which is why it is mentioned).