I happened to see the 2006 movie Freedomland recently. The link will take you to a Wikipedia page that explains the plot. In brief, a young boy is missing, then found dead. Accusations are made against innocent people until the tragic truth is discovered. The lead characters are Julianne Moore as the boy’s mother and Samuel L. Jackson as the police detective. When the detective visits the boy’s mother in prison, he reflects upon his own personal history and tells her: “God’s grace is sorta like retroactive.”
What he means by this is that God’s grace has touched his life, giving him a chance to make up for past failures. That he can recognize this in his own life suggests that the same grace is available to her.
Even for people (like all of us) who have made mistakes, done things for which they have difficulty forgiving themselves, entrapped themselves in spirals of guilt and regret, God’s grace is available. It’s present; it’s future; it’s even retroactive. And if we think that our mistakes reveal our weaknesses, all the better.
In 2 Corinthians, Paul writes of asking God to rid him of a particular torment, a thorn in his flesh, but in response to his pleading, God said: “My grace is sufficient for you, for my power is made perfect in weakness” (NIV). The Amplified text spells it out more clearly: “My grace (My favor and loving-kindness and mercy) is enough for you [sufficient against any danger and enables you to bear the trouble manfully]; for My strength and power are made perfect (fulfilled and completed) and show themselves most effective in [your] weakness.” [2 Corinthians 12:9]
Our only role when it comes to God’s grace is to accept it.