Jeffrey Arthur grounds preaching as proclamation about the memory of the God who remembers his people and forgets their sins, because those people are inclined to forget about the grace of God and focus on their sin.
As practical theology, preaching as reminding is built on theology proper — the character and actions of God. Because he remembers his covenant and forgets the sins of his children, promising never to leave or forsake them, ministers take their stance as the Lord’s remembrancers, reminding the baptized that nothing shall separate them from the love of God in Christ Jesus. But preaching as reminding is built on a second foundation also, one related to human nature: we are prone to forget.
Jeffrey D Arthurs, Preaching As Reminding, IVP, 2017, pg 25.