It is in this chapter that Ruth makes an appeal to Boaz because of Naomi's advice. Naomi's intent was to seek physical security for her daughter-in-law. At that point in time, Ruth was a foreigner in Israel with no one to provide for her other than herself. She had no husband or father to care for her. She was vulnerable consequently. Naomi desired to help her daughter find more stability. She wanted Boaz to become the provider and protector of Ruth.
Naomi's plan was simple. She knew where Boaz would be that night. She intended to send Ruth to Boaz at a time that wouldn't interfere with either his work or eating. This would ensure that Ruth would find him undistracted, content, and hopefully receptive to her message. Ruth would wear her best garment, after washing and anointing herself, in an attempt to make the most favorable impression.
For Ruth to lie down quietly at Boaz's feet was an acceptable way for her to make a claim on him as her near-kinsman (or close relative). It should be understood that Naomi, by law, had the first claim which was to be exercised upon the closest relative. But, in her sending of Ruth she rejected the claim for herself and transferred it to her daughter-in-law. It will be learned later in this chapter, however, that Boaz was not the closest relative to these women. This fact would complicate the situation.
"So she [i.e., Ruth] went down to the threshing floor and did according to all that her mother-in-law instructed her. And after Boaz had eaten and drunk, and his heart was cheerful, he went to lie down at the end of the heap of grain; and she came softly, uncovered his feet, and lay down. Now it happened at midnight that the man was startled, and turned himself; and there, a woman was lying at his feet. And he said, 'Who are you?' So she answered, 'I am Ruth, your maidservant. Take your maidservant under your wing, for you are a close relative'" (Ruth 3:6-9).
Boaz was startled in the middle of the night; perhaps he sensed someone's presence with him. Ruth was patiently lying at his feet. Some would like to read sexual immorality into this incident, but there is nothing here but purity. There is no indication that there was any bodily contact at all. He did not wake up from an attempt on her part to make an immoral advance. She was still lying at his feet when he woke up, and she remained there until morning (3:14). Additionally, Boaz referred to her in 3:11 as a "virtuous woman". It is difficult to believe he would make such a claim if they were involved at that time in illicit activity.
Ruth entreated Boaz to take her under his wing (i.e., under his care and protection). In other words, she wanted him to acknowledge her claim and take her in as his wife since he is a close relative (cf. Deut. 25:5ff).