What is the meaning of "Lini ha'Laylah"?
Rashi, from Rus Rabah 6:4: Spend tonight without a husband. You will not spend another night without a husband!
Malbim: You need to lodge here tonight until morning, when I will speak with Tov, the closer Go'el.
Why did he say "Chai Hashem"?
Rashi #1: She said, do you dispel me with words?! He swore not to do so. Malbim - if Tov will not want to redeem you, I swear to do so. His Shevu'ah was also against his Yetzer (refer to 3:13:2:2).
Rashi #2, from Rus Rabah 6:4: His Yetzer was inciting him - you are single and she is single. Have Bi'ah with her! He swore to do so only via Nisu'in.
Why did he say "Shichvi"?
Malbim: She wanted to rise from lying at his feet. He said, you need not - I do not fear lest my Yetzer ha'Ra entice me to have Bi'ah with you now.
