It’s fun to do the detective work, but GOSH I wish people would just link to where they found images like these!
The text is from the Psalms, and those tall, narrow Gothic letters looked English and late medieval, so I Googled “psalter” and “Innocents” and “14th century,” and discovered that the image is from the 14th-century Queen Mary Psalter, British Library, Royal Ms BVII, fol 132r.
Holy Innocents