לא המתים יהללו י-ה

From Maran HaRav Hutner in Ma'amarei Pachad Yitzchak, said on Hoshana Rabba:

The pasuk says "Lo hameisim yihalelu y-oh ... vi'anachnu nivareich y-oh may-atah vi-ad olam halleluy-oh" - The simple meaning is that dead people can no longer praise Hashem but we will praise him forever.

The simple understanding is erroneous.

The true meaning is that mortal being cannot praise Hashem. [צו דען וואס א מענטש דרייט זיך דא ארום אויף דער וועלט זיביצעק יאר איז אים מוציא מכלל מתים -  That a person walks around the world for 70 years excludes him from the category of "dead person"?] But we who are going to live forever after tchiyas hameisim will praise Hashem forever.