What is the speaker saying in the last two lines of this verse still wouldst thou sing and i have ears in vain to thy high requiem become a sod

Still wouldst thou sing and i have ears in vain

to thy high requiem become a sod

The speaker is expressing his feelings of sadness with some touch of regret because the other person will continue to sing but he could no longer hear it. The song will become a requiem or songs of prayer for the dead and will become a sod or the crust of the ground. In other words, the speaker will be dead or is dying and he feels that the other person's singing will only serve as covering to his corpse that will have been buried under the ground.