God's wrath is coming, do your utmost to escape before it's too late. In context, if I remember correctly he is referring to the destruction of Sodom and Gommorah. Lot's wife looks back and turns into a pillar of salt. During the days of his ministry, he might have used this as a warning to to his congregation, telling them to flee from their past lives and live a Godly life...... not looking back to the sin and lives they've escaped.
early 18th century: from French pédestre or Latin pedester ‘going on foot’, also ‘written in prose’ + -ian. Early use in English was in the description of writing as ‘prosaic’, and because the root wood is "foot"