Definitions: (1) having great bodily strength or physical power; very robust or vigorous; commanding; (2) wonderful; colossal; (3) important; momentous; (4) of high status <said of kings and others with the highest rank>

Today’s mighty oak is just yesterday’s nut, that held its ground. David Icke (1952-) English author

The world is moved along, not only by the mighty shoves of its heroes, but also by the aggregate of tiny pushes of each honest worker. — Helen Keller (1880-1968) American author & lecturer

Comment: Although one can be mighty of mind, this quality is most often reserved for physical prowess. Although there have been quite a few who were so mighty of spirit as to make ripples (and even waves) through time.