Why does it say "Lachen"?
Rashi: Because you did not want to listen. Radak - it is best to say that this discusses the generation of Chizkiyah, like the previous Parashah. Until now discussed the Resha'im who sought help from Egypt; this verse discusses the Tzadikim - Chizkiyah and his entourage. Some tie this verse to the coming Parashah of the future.
Malbim: Because you did not listen to His voice.
What is the meaning of "Yechakeh Hashem Lachananchem"?
Rashi: He will not skip (pardon) for you the evil decree in order to rush to bring the good on you. Rather, wait until its end comes.
Radak: Yechakeh is Po'el Yotzei (it acts on others); He promises you to wait for Him to grace you. He will grace and support you. This is like "Al Asher Yichaltani" (Tehilim 119:49). Lachananchem is Lachanan (to grace) you. Its grammatical form is like "Ein Gacheles Lachmam Ohr" (47:14).
Malbim: He will wait a long time before He graces you.
What is "Yarum"?
Rashi: It is being distanced.
Radak: He will rise over Machaneh Ashur to have mercy on you.
Malbim: When afflictions befall you, normally He has mercy; He cannot see His nation afflicted - "b'Chol Tzarasam Lo Tzar" (63:9). He will rise to Shamayim and hide His eyes from you, lest He have mercy on you.
Why does it say "Ki Elokei Mishpat Hu"?
Rashi: First He collects 'payment' from those who rebel against Him.
Radak: The Tzadikim will not perish with the Resha'im.
Malbim: This is why He will delay grace and mercy; first you must receive punishment for your sins.
For what do they wait for Him?
Rashi: For the consolations that He promised; no word [of His] will fall (unfulfilled).
Radak, Malbim: To save them.