What is "Refah ha'Yom"?
Rashi: The sun is weak, i.e. not in its strength 1 , and leans La'arov (to set in the Ma'arav (west)).
Radak: The sun is in its strength at midday. "K'Tzeis ha'Shemesh bi'Gvuraso" (Shoftim 5:31) - from sunrise until Gevuraso (midday) it gets stronger; after this, its heat and light weaken.
What is "Chanos ha'Yom"?
Rashi: It is when all travelers veer to be Choneh (lodge) in a house (for it is proper to cease traveling before sunset - Ta'anis 10b).
Radak #1: It is night. During the day a person goes here and there, and at night he camps.
Radak #2: It is Chanos of the sun. At night, it seems that the sun camps (stops). Even though it goes (around from west to east, under the earth), since it is hidden from man's eye, it seems that it stopped its trajectory.
How did he try to convince him to stay?
Malbim citing Mahari: It is late in the day, and time to lodge. In any case you will not get home today, and you will need to lodge on the road. Lodge here, and rise early in the morning and you will get home in one day, and you will not need to lodge on the road!
