Yesterday has passed forever beyond our control. All the money in the world cannot bring back yesterday. We cannot erase a single thing we've done, we cannot change a single word we've said. Yesterday is gone. The other day we should not worry about is tomorrow.
Tomorrow is also beyond our immediate control.
Tomorrow's sun will rise either in splendor or behind a mask of clouds, but it will rise. Until it does, we have no stake in it, for it is as yet unborn. That leaves only today. Anyone can fight the battles of just one day. It is not the experience of today that drives us mad, it is remorse or bitterness over something which happened yesterday and the dread of what tomorrow may bring.