What is the basis of the teaching that souls in purgatory can intercede for the living?

Point 6 in the Our Sunday Visitor Article ["9 truths about purgatory"](https://www.osvnews.com/2013/09/18/9-truths-about-purgatory/) is that souls in purgatory can intercede for us: > The souls in purgatory can’t do anything for themselves, but the Church has long believed that they can do something for us: They can pray for us, helping obtain for us the graces we need to follow Christ more perfectly. Two other questions related to their consciousness while in purgatory, given their status as [disembodied souls](https://cct.biola.edu/thomas-aquinas-human-nature-soul-afterlife/) : 1. Whether they can hear our petition for them to intercede for us, or whether the initiative to intercede for us can only come from them? 2. Whether they retain the memory of their loved ones on earth so they can intercede for us? **What is the Catholic teaching on this: from Scripture, Magisterium, and/or respected saints & theologians?**