In brief, the Desert Mothers were third- and fourth-centry acetic, monastic women who took to the Egyptian desert. They, and the Desert Fathers, often developed a reputation as spiritual teachers. Their wisdom continued as an oral tradition and later set down.
Here are two sayings from particulary well-regarded Mother Syncletica:
Do not let yourself be seduced by the delights of the riches of the world, as though they contained something useful on account of vain pleasure. Worldly people esteem the culinary art, but you, through fasting and thanks to cheap food, go beyond their abundance of food. It is written: "He who is sated loathes honey." (Prov. 27.7) Do not fill yourself with bread and you will not desire wine.'
She also said, 'Those who have endured the labours and dangers of the sea and then amass material riches, even when they have gained much desire to gain yet more and they consider what they have at present as nothing and reach out for what they have not got. We, who have nothing of that which we desire, wish to acquire everything through the fear of God.
(Apophthegmata Patrum: The Sayings Of The Desert Fathers, Sr. Benedicta translation)