The phrase "earnest prayer" means a sincere and heartfelt request or plea made to a higher power, with genuine intention and seriousness. Full definition
God reveals knowledge to mankind in science and medicine because people have asked God in earnest prayer for knowledge. (religion.blogs.cnn.com)
Yet churches and synagogues evoke awareness of the cycles of life; they call to mind earnest prayer and resolve, the observances of birth, marriage and death. (religion-online.org)