It's not a statement. It's a recitation of history. And few events say more about Honest Abe's character than his behavior during the incident know as the Baltimore Plot.
ML/NJ
It's a figment of your imagination. Mary Lincoln and the rest of the Lincoln family arrived after Lincoln did, that much is true. They arrived about 12 hours later. During that time Lincoln met with key Republicans, President Buchanan, and some office seeker, and rode around Washington with Seward. His presence in Washington was common knowledge long before Mrs. Lincoln left Harrisburg. They were never in any danger, unless you think the rebel mob would have deliberately targeted woman and children.