The soul, the spirit, that deep inner element in a human being which lives forever and is destined for either eternal glory or eternal horror. needs the presence of God. After the fall into sin in the early chapters of human history that presence was removed from humanity. We became a thirsty human race. Work relationships grow creaky. Individuals wake up one day with all the toys they could ever want and discover that, no, it is not so that the one with the most such toys wins.
Jobs vaporize in downsizing or some massive corporate reorg.
Houses get washed away by swollen spring rivers. There's got to be more - cries the thirsty soul . I thirst cries Jesus. He thirsted physically. He also took on the thirst of the human spirit separated from the Spirit of God.