The answer is lament, praise, consolation.
The first stanza recognizes the part Lincoln played in winning the Civil War. That stanza ends with a lament, or a passionate, mournful expression of grief. The second stanza praises Lincoln, idealizing him as a leader and father. The final stanza returns to the nation's victory to give consolation and urge the nation to exult, or celebrate, while affirming the poet's own "mournful tread."