"Praised be Jesus Christ crucified, dear son of the glorious Virgin Mary.
Oh most delightful and very dear brother, ransomed, like me, by the precious blood of God's dear Son, I, the unworthy Catherine, write to you, obliged by Christ crucified and by His sweet Mother Mary to beseech you and press you to relinquish and abandon your insensibility and the obscure unfaithfulness, in order to return and receive the Grace of holy baptism, for without baptism you cannot have God's Grace. Whoever is not baptized does not share in the benefit of the holy Church; but like a rotten member cut off from the congregation of Christian faithful, goes from temporal to eternal death, and with reason accrues punishment and gloom; since he has not wished to wash in the water of holy baptism, and has despised the blood of God's dear Son, which He so lovingly shed. Oh very dear brother in Christ Jesus, open your mind's eye to contemplate His inestimable charity, which He sends you, inviting with holy inspirations which you had in your heart; and through His servants He requires and invites you to settle with Him, not taking into account the long war and insult He has received from you due to your unfaithfulness. Since our God is so sweet and loving, that after the law of love came and the dear Son of God came through the Virgin Mary, and shed His whole blood upon the wood of the most holy Cross, we are able to receive the fullness of divine mercy. Whence just as the law of Moses was founded on justice and on punishment; so the new law given by Christ crucified, life from the Gospel, is based on love and mercy. For He is sweet and compassionate, provided that a person returns to Him humble and faithful, believing to have eternal life through Christ. And it seems that He does not wish to remember the offences that we tender Him; and He does not want to condemn us for all eternity, but always shows mercy. Therefore rise, my brother, when you want to be associated with Christ, and do no longer slumber in so much blindness, since God does not want it so, nor do I, that you be blind when you die; but I ardently desire you to receive the light of holy baptism, just as the thirsty deer longs for running water. Do not resist any longer the Holy Spirit who calls you, and do not despise Mary's love for you, nor the tears and prayers shed and said for you; because your trial would be too great. Stay in the holy and sweet delight of God; and I ask Him, who is Truth itself, to enlighten us and fill us with His most holy grace, and fulfill my wish in you, Consiglio. This was given to you, Consiglio, by Christ Jesus. Praised be Christ crucified, and His most sweet Mother, glorious Virgin, Our Lady Holy Mary. Sweet Jesus, Jesus love."

Saint Catherine of Siena, Doctor of the Church: Letter n.15

Prayer:

O God, You created all peoples and redeemed them through Your Divine Son's Blood. We ask You through the intercession of St. Catherine to live in coherence with faith as she did, adopting an attitude of charity and respect towards our elder brothers, heirs of the Promise.
We ask You this through Jesus Christ, Our Lord, who with You lives and reigns in the unity of the Holy Spirit for ever and ever. Amen

By Ateneo Pontificio "Regina Apostolorum"