NFL Legend Aeneas Williams -- CLEANING UP FERGUSON ... Boarding Up Windows

Aeneas Williams -- one of the best defensive players in NFL history -- is hitting the streets of Ferguson ... helping to repair the city one shattered window at a time.

The Hall-of-Famer -- who's also a pastor in St. Louis -- rounded up a crew of people and is boarding up some of the windows that were smashed during the melee last night.

"Love Never Fails! Love is an ACTION WORD! I SEE A LOT OF LOVE HERE IN FERGUSON," Williams tweeted.

"After all the finger pointing is done, my [question] is what are we going to do now? Answer LOVE."