Let me just say that in the very grand world of music it is quite intimidating to have to find one piece with just ONE CHORD that you need, meaning that you would think it would be easy but soon find that not every composer likes augmented sixths chord. I searched through all of my proficiency pieces and failed, looked at my musical theatre scenes music and failed, and finally just started flipping through one of my Schubert anthologies and STRUCK GOLD!
Litanei is from the Feast for All Souls Day. This holiday is used to commemorate the faithful who have departed. I found a lovely French augment sixth chord in measure 8 that resolves to a very strong FIVE chord. This augmented sixth chord is falls on the text three times because the melody is repeated with different text three different times. It falls on 1) all who have passed 2+3) all that have, in both cases it is referring directly to the souls of those who have already gone. I think that the composer chose to do this because he was trying to create a kind of eerie effect and combine the idea of the soul having moved on but still being present, or else they would not be remembering them. If I were performing this I would use the augmented chord to help me feel a sense of remembrance for those who have already gone, which is both a happy and sad idea. It would help me contrast the repetitiveness of the word "alle", all the, because the first time it is accompanied by the augmented chord and the phrase talks about all those who have departed, or left this world. and then in the next statement after the fermata on the five chord, it is harmonized by a one chord which it also eventually resolves to, all though in an inversion, and the phrase accompanying this says all souls rest in peace. This statement contrasts the earlier eeriness of the augmented chord because it gives a sense of strength and encouragement thinking that those who have past are now resting in peace and not in limbo somewhere...unlike the first statement which implies that the souls are simply gone...to no place in particular.