St. Alphonsus de Liguori’s sermons on the spiritual life are available in free-to-download audio format @ traditionalcatholicsermons.org/index_files/SermonsOnTheSpiritualLife.htm
Be advised that the website is affiliated with the Congregation of Mary Immaculate Queen (CMRI) (Latin: Congregatio Mariae Reginae Immaculatae), a sedevacantist group in schism with Rome. Some of the audio sermons below those of St. Alphonsus (e.g. Bishops Dolan and Sanborn’s) are unfortunately laced with sedevacantist accusations against Rome and the Holy Father, and as such cannot be recommended. However, St. Alphonsus’ sermons are read directly from his writings and are direct, enlightening and orthodox.
These sermons served as my introduction to the holy man who was a bishop, confessor, Doctor of the Church, founder of the Redemptorists, mission preacher, mystic and theologian. May those who listen to them find them beneficial in their spiritual journeys.