The passuk says Hashem is ארך אפים. ארך אפים literally means lengthens, or is slow to anger. Rashi explains Hashem lengthens His anger and doesn’t hurry to punish so a person will have an opportunity repent.
The Tomer Devorah says when a person sins he is rebelling against Hashem who created him and continuously gives him the ability to exist. In truth Hashem should say “you are rebelling against Me, so keep yourself alive.” Obviously a person cannot keep himself alive and that would be the person’s end. Out of Hashem’s kindness and mercy He sustains us and gives us an opportunity to repent.
Onkelos translates these words as מרחיק רגז, meaning distancing anger. The Yerushalmi in Ta’anis brings on the words מרחיק רגז: R’ Levi gives a mashal to a king who had two strict officers. The king said, “If they dwell near me then when someone angers me, these strict officers will enact judgment immediately. Therefore, I am going to send them far away. If anyone will upset me, there will be time for them to appease me until I send for the officers and they come.” So too, אף and חמה are angels of destruction. Hashem said, “I am going to send them far away, so in case Yisroel will sin, there will be time for them to do teshuva before אף and חמה, the malachim of anger and destruction, come back to Me.” The term “distance anger” refers to sending away the two angels of destruction from the mechitza of Hashem.
May we learn from Hashem’s chessed to do teshuva, and to give people chances to correct themselves and forget and forgive.