Marina experienced visions of a number of saints, and within her lifetime she acquired a reputation throughout Spain as a holy woman, especially in her home city of Valladolid.

Despite taking a vow of chastity, spending her life in prayer and service, and gathering a small community of other women around her, Marina never joined a religious order.

She was popularly venerated after her death, and her confessor, Luis de la Puente, collected and prepared her accounts of her spiritual experiences.

[1] Her father, Diego de Escobar, was a professor of civil and canon law, a lawyer in the Royal Chancellery of Granada, and, for a time, governor of Osuna; her mother was Margaret Montaña, daughter of the Emperor Charles V's physician.

Teresa discouraged Marina's ambition to join one of her discalced Carmelite convents, reportedly saying: "Come now, daughter, you don’t have to be a nun since God wants you for great things from the corner of your house.

[4]: 207  In a 1621 vision, Marina reported that Ignatius of Loyola appeared to her, telling her that he adopted her as a member of the Society of Jesus and clothing her in the habit of the order.

[8][4]: 202  There, although bedridden after a 1603 accident, she gradually accumulated a group of about twenty women, engaged in making clothing for the poor and teaching the younger girls.

The collected writings were brought before the Spanish Inquisition under suspicion of heresy; it was suggested that Marina might be exhibiting alumbradismo or Quietism, and that her visions might not have been authentic.

[3] Edward Graham, in the Catholic Encyclopedia, describes the writing as "free and flowing", and Marina's style as displaying "simplicity and naïve frankness".

[3] On the other hand, de la Puente describes Marina's writing as "wordy and sloppy; she repeats something several times in order to make herself understood, and with too many words.