An Extemporary Acrostic

My Muse, once more, thy aid I humbly claim;
Refuse not now to grace my rustic lays.
Johnston or Pope might well befit the theme
Or Grecian bards, who ever merit praise.
How dares my humble hand assume so high?
No common character inspires my song,
His growing fame long since has reach'd the sky:
All I can say but does his virtues wrong;
Let then my blund'ring pen in silence rest;
Lo, silent admiration paints them best.