Why does it say "b'Or Pnei Melech Chayim"?
Rashi: One on whom Hashem 'smiles', this is life for him. Therefore, one must straighten his way in front of Him.
R. Yonah: Ohr Pnei Melech is more than Ratzon. It shows great love that is constant. This shows the great level of seeking Retzon Hashem - even regarding mortal kings it is esteemed! One should toil and strive to acquire it 1 .
Malbim: This refers to above - Ish Chacham atones for anger (14). The messengers of death depart. When the King's face illuminates, this shows that anger departed; out comes life, the opposite of death.
What is the significance of "u'Rtzono k'Av Malkosh"?
Rashi: One who is pleasing to Hashem, this is good for him like a cloud that brings rain.
R. Yonah: When Hashem desires one of His servants, the benefit is connected to the desire. It is not in doubt, and it will not be found in the future. It is already found with the Ratzon, just like if clouds are full of rain, the benefit is already there - "Im Yimal'u he'Avim Geshem Al ha'Aretz Yariku" (Koheles 11:3). There is no doubt about the benefit, like "Ki Ka'asher Yered ha'Geshem veha'Sheleg Min ha'Shamayim