And [Joseph's brethren] told [Jacob] all the words of Joseph, which he had said unto them...the spirit of Jacob their father revived: And Israel said, It is enough; Joseph my son is yet alive: I will go and see him before I die. - Genesis 45
I wonder at this setting often when I read and think through this passage. Imagine after all these years, with hard things in between occurring (Judah & Tamar, Reuben & Billhah, Dinah's being made "common," and the sons of Jacob murdering all the men of Shechem's and Hamor's city), then hearing one of the greatest sources of your grief, Joseph's death by wild animal, was not so, but was yet another product of those closest to you. Few and evil were his days assuredly! It's fascinating how Jacob carries on, and while the news of Joseph's living estate is a relief, what difficulties it must have been to work through with his sons.
Yet -on such a larger scale- imagine the Lord's patience with all of His children? I am confident that Jacob's sons' sins were occasion for Jacob to remember his own sins, being styled a supplanter, working before by hook & crook, etc. So Jacob -while perhaps his failures not being of the same kind as his sons- nevertheless probably considered his own fallenness when deliberating on the transgressions of his sons, of course addressing many things in his blessings of them later.
But our heavenly Father is not like Jacob. He is holy. Wholly holy. Altogether righteous. He cannot/will not sin, nor look upon it. And, while earthly fathers can have sinful patience with their children (and by that, I mean, indulging it where it should not be indulged), the Lord's "patience" against our sins was not a mere sweeping under the rug. No, He is holy, harmless, undefiled, and separate from sinners, took our sins upon Himself, and the Father dealt out the punishment upon Him! The Lord's patience with us has a definite and guaranteed goal. Namely, our sanctification.
The primary use of this truth, of course, is the glory of the LORD, our praising His Name for so great salvation, magnifying His grace toward sinners who deserve -in themselves- nothing but wrath and condemnation. A secondary use, then, is -considering the great debt we've amassed against God (Who is perfection, not like earthly fathers), and His subsequent forgiving us our trespasses- how much more so we, fallen creatures, are to be forward in forgiving others offenses and trespasses against us!