Isaiah 38:18 - Matthew Poole's English Annotations on the Holy Bible

In this and the following verse, he declares God's design in delivering him, that he might praise him in his church, which if he had died he could not have done. The grave cannot praise thee; the dead are not capable of glorifying thy name among men upon earth; which I desire and determine to do. See the like expressions, Psalms 6:5, Psalms 30:9 88:10, &c. The grave is put for the persons lodged in it by a metonymy. Cannot hope for thy truth; they cannot expect nor receive the accomplishment of thy promised goodness in the land of the living.