Ruth 4:1

The man was so virtuous that he did not rush into a marriage outside the law, but he spoke with his neighbors about the marriage. However, his words are also worthy of admiration. For his first words were not about the marriage but about the possession of fields, etc. Moreover, when, on account of the prospective marriage he [the relative] in fact refused the contract for the land and indeed took off his sandal and gave it to Boaz, in accordance with the law, Boaz then took Ruth to be his wife. Furthermore, because he was not serving lust, he took her in the spirit that one should take a wife, and his words also showed themselves worthy of praise, You are witnesses today, etc. "I do not," he said, "transgress the law in marrying a Moabite woman; rather, I diligently fulfill divine law, so that the memory of the dead is not extinguished."

When Ruth entered the land of Israel with her mother-in-law, it was provided (on account of the merits of her prayers) that she be married to a man of the lineage of Abraham and whom, indeed, she at first believed to be her closest kinsman. He [the nearest kinsman] said that he could not marry her and, when he had withdrawn, Boaz was married to her, with the witness of ten elders. He [Boaz] who previously confessed himself unable to marry that same woman was united with her and was blessed by those ten elders.It is thought that this passage prefigures John the Baptist who, when he himself was thought by the people of Israel to be Christ and was asked who he was, did not deny who he was but confessed it, saying that he was not Christ. And those who were sent persisted in these inquiries about who he was. He answered, "I am the voice crying in the desert." He confessed the good news about the Lord, saying, "He who has the bride is the bridegroom." He showed that he himself was the friend of the groom [the best man], since he added, "Truly, the friend of the groom is he who stands and hears him and rejoices on account of the groom's voice." And so they thought he was Christ, because they did not understand that Christ had come on the day of the visitation and that he who was earlier promised by the prophets' voices was the church's bridegroom. But just as he told her he was not her kinsman but then afterwards Ruth was united with Boaz, so Christ, who is the true bridegroom of the church, whom the sayings of all the prophets proclaim, was deemed worthy, from all Gentile nations, to claim the church, to present to God the Father unnumbered people throughout the whole orb of the world, because his kinsman took off the sandals.