Yesterday Is Gone Tomorrow Has Not

This quote is cited from Teresa's book In the Heart of the World: Thoughts, Stories & Prayers (New World Library, p. 17), which is the most specific published source found for the exact wording. The Crossroads Initiative, a Catholic organization that vets Teresa quotes for authenticity, also includes it in their confirmed collection. The sentiment echoes themes from contemplative traditions that predate Teresa — similar expressions appear in 19th-century Christian devotional literature — but the present-tense urgency of "Let us begin" is characteristic of her practical, action-oriented spirituality.