August is a month dedicated to the Immaculate Heart of Mary. Pope John Paul II encouraged devotion to Mary in his Apostolic Letter Rosarium Virginis Mariae.
St. Augustine said of Mary "she cooperated through charity in the work of our redemption". Devotion to the Heart of Mary began in the Middle Ages under Anselm of Canterbury, and Bernard of Clairvaux. It was further developed by Mechtild, Gertrude the Great and Bridget of Sweden. St. John Eudes (d. 1681) propagated the devotion, and made it public.
Pope Pius XII instituted the feast of the Immaculate Heart of Mary in 1944 to be celebrated on the 22nd of August. In 1969, Pope Paul VI moved the celebration of the Immaculate Heart of Mary to the day, Saturday, after the Solemnity of the Sacred Heart of Jesus. Pope Paul VI moved the celebration of the Queenship of Mary from 31 May to 22 August.
I give Thee thanks for that Thou hast annihilated Thyself, taking the form of a slave in order to rescue me from the cruel slavery of the devil. I praise and glorify Thee for that Thou hast been pleased to submit Thyself to Mary, Thy holy Mother, in all things, in order to make me Thy faithful slave through her. But, alas! Ungrateful and faithless as I have been, I have not kept the promises which I made so solemnly to Thee in my Baptism; I have not fulfilled my obligations; I do not deserve to be called Thy child, nor yet Thy slave; and as there is nothing in me which does not merit Thine anger and Thy repulse, I dare not come by myself before Thy most holy and august Majesty. It is on this account that I have recourse to the intercession of Thy most holy Mother, whom Thou hast given me for a mediatrix with Thee. It is through her that I hope to obtain of Thee contrition, the pardon of my sins, and the acquisition and preservation of wisdom.
Hail, then, O immaculate Mary, living tabernacle of the Divinity, where the Eternal Wisdom willed to be hidden and to be adored by angels and by men! Hail, O Queen of Heaven and earth, to whose empire everything is subject which is under God. Hail, O sure refuge of sinners, whose mercy fails no one. Hear the desires which I have of the Divine Wisdom; and for that end receive the vows and offerings which in my lowliness I present to thee.
I, (name)_____, a faithless sinner, renew and ratify today in thy hands the vows of my Baptism; I renounce forever Satan, his pomps and works; and I give myself entirely to Jesus Christ, the Incarnate Wisdom, to carry my cross after Him all the days of my life, and to be more faithful to Him than I have ever been before. In the presence of all the heavenly court I choose thee this day for my Mother and Mistress. I deliver and consecrate to thee, as thy slave, my body and soul, my goods, both interior and exterior, and even the value of all my good actions, past, present and future; leaving to thee the entire and full right of disposing of me, and all that belongs to me, without exception, according to thy good pleasure, for the greater glory of God in time and in eternity.
Receive, O benignant Virgin, this little offering of my slavery, in honor of, and in union with, that subjection which the Eternal Wisdom deigned to have to thy maternity; in homage to the power which both of you have over this poor sinner, and in thanksgiving for the privileges with which the Holy Trinity has favored thee. I declare that I wish henceforth, as thy true slave, to seek thy honor and to obey thee in all things.
O admirable Mother, present me to thy dear Son as His eternal slave, so that as He has redeemed me by thee, by thee He may receive me! O Mother of mercy, grant me the grace to obtain the true Wisdom of God; and for that end receive me among those whom thou lovest and teachest, whom thou leadest, nourishest and protectest as thy children and thy slaves. O faithful Virgin, make me in all things so perfect a disciple, imitator and slave of the Incarnate Wisdom, Jesus Christ thy Son, that I may attain, by thine intercession and by thine example, to the fullness of His age on earth and of His glory in Heaven. Amen.