"And we know that all things work together for them that love God, to them who are called according to his purpose." - Romans 8:28 (Audio)
Here are some sermons on Romans 8:28:
The Worst Things, by Thomas Watson (1620-1686)
The True Christian's Blessedness, by Pastor Charles Haddon Spurgeon (1834-1892)
Overcoming Depression, Melancholy, and Overmuch Sorrow, #2, by Richard Baxter (1615-1691)
God's Strange Agents in Answering Our Prayers, by Dr. Ian R. K. Paisley (1926-2014)
Secure in God's Everlasting Arms, by Dr. Alan Cairns
Rays of Spiritual Optimism for a New Year! by Rev. Ian Brown
There is a wonderful hymn based on Romans 8:28 titled: All Things Worked Out for Good. One of the verses goes like this:
"Someday the path God chose for me,
will all be understood.
In heaven's clearer light I'll see,
all things worked out for good!"