"Men" says St. Thomas, "vow in baptism to renounce the devil and all his seductions." "This vow," says St. Augustine, "is the greatest and the most indispensable of all vows." Canon Law experts say the same thing: "The vow we make at baptism is the most important of all vows." But does anyone keep this great vow? Does anyone fulfil the promises of baptism faithfully? Is it not true that nearly all Christians prove unfaithful to the promises made to Jesus in baptism? Where does this universal failure come from, if not from man's habitual forgetfulness of the promises and responsibilities of baptism and from the fact that scarcely anyone makes a personal ratification of the contract made with God through his sponsors?
This is so true that the Council of Sens, convened by order of the Emperor Louis the Debonair to remedy the grave disorders of Christendom, came to the conclusion that the main cause of this moral breakdown was man's forgetfulness of his baptismal obligations and his disregard for them. It could suggest no better way of remedying this great evil than to encourage all Christians to renew the promises and vows of baptism. "
Source: St. Louis de Montfort from True Devotion to Mary