In the second account of creation in the Book of Genesis (2:4-25), God breathed life into clay from the earth. God's very spirit enlivens human beings, as we are made in the divine image. (The Hebrew word for "human" means "breathing clay.")
The prayer of the Church buries the faithful with the words: earth to earth, ashes to ashes, dust to dust. It is a natural and normal process to return to the earth from which we are made. This return to the earth is the essence of in-ground burial customs. The practice is deeply embedded in the Judeo-Christian tradition.
Burial in the earth has close connections with the natural processes of planting, growing, reaping and dying. With solid confidence we place a seed in the earth. We abandon and bury a seed believing in the warmth of the sun, the nutrients of the soil and the moisture of timely rains. A seed has no machinery inside. Yet, who doesn't remember the first seed we planted...at school, in the garden, on the window sill.
Jesus said, Unless a grain of wheat falls to the ground and dies, it remains just a single grain of wheat; but if it dies, it produces much fruit (John 12:24).