The Lord is not slow in keeping His promise, as some understand slowness. Instead, He is patient with you, not wanting anyone to perish, but everyone to come to repentance.
2 Peter 3:9
Words: John M. Orrock, 1905. Appeared in Carols of Hope, edited by Clarence M. Seamans, et al. (Boston, Massachusetts: Advent Christian Publication Society, 1906), number 40, alt.
Music: Edward M. Fuller (🔊 pdf nwc).
If you know where to get a good photo of Orrock (head & shoulders, at least 200×300 pixels),

The King and the kingdom are coming
Tho’ long has the waiting time seemed;
And oft, to the eye of the watcher,
A light in the distance has gleamed,
But only to go out in darkness
And leave the heart sad as before;
Be patient a little while longer,
The waiting time soon will be o’er.
The crown is a thing of the future,
The glory will yet be revealed;
The gift royal has not gone by thee,
Nor Jesus His promise repealed.
Be faithful a little while longer,
The night must give place to the day:
The King and the kingdom are coming,
And for their arrival we pray.
Our prayer is the prayer of the ages,
Which Jesus Himself taught to men;
And thus He is pledged to performance
Without telling all about when;
So, praying, and hoping, and working,
In faith to each other we cry:
The King and the kingdom are coming,
Keep heart, for the time draweth nigh.