What two groups made up the crowd that waited outside the federal arsenal?

The raid on Harper's Ferry was an intent by John Brown, who was an abolitionist, to initiate a slave revolt in 1859 by taking control on the federal arsenal located in Harper's Ferry, Virginia.

The two groups that were outside the arsenal were:

John Brown's "group of 22". This group of men was supposed to be supported abolitionists Harriet Tubman and Frederick Douglass. However, none of them showed up in the scene, as Tubman fell ill and Douglass was doubtful of a victory. A group of US Marines led by Colonel Robert E. Lee.

The attempt was unsuccessful, resulting in the defeat of Brown's group by the US Marines.