Part of a profound statement by Francois Andre Danican-Philidor (better known just as Philidor) and possibly the most known quote in chess.
The full quote is:
"Pawns are the soul of the game. They alone create attack and defense, the way they are deployed decides the fate of the game."
All good chess players should understand the deep meaning behind this snippet of wisdom. Every pawn move is permanent -- unlike other pieces, they cannot move backwards. Each pawn movement opens or closes diagonals and files and each pawn capture opens or closes a rank. Each pawn carries the potential to be promoted into a Knight, Bishop, Rook or Queen, an occurrence that usually determines the fate of the game.
Pawn positions often determine the way the game goes. Passed pawns, isolated pawns and doubled pawns reveal long term strengths and weaknesses. A line of pawns forms the basic defense for the castled king and yet can become the king's own grave in the case of a back rank mate.
In openings, pawns jostle for control of the centre and play the major role in opening and closing avenues of attack. Interesting midgames often involve pieces circling around on both sides of a pawn advance, one side gathering pieces around to support the pawn steamroller, the other trying to tear it down. Endgames commonly revolve around attempting to advance a pawn to the last rank.
Pawns ... the most expendable piece ... the footsoldiers thrown into battle as cannon fodder ... and yet pawn moves are the moves that are usually deliberated longest upon ... except by those who do not know better.