"
When, my, time comes around
Lay me gently in the cold dark earth
Hozier is talking about war here. "Lay me gently in the cold dark earth" is saying that when he dies at war, he wants to be laid at rest. The song is about his lover, so the following lines, "No grave can hold my body down, i'll crawl home to her" is exemplifying that even if he does die, he will always be with the love of his life.