The ShikkerDovid is learning Moed Kattan for dovid ben yitl a’h. The first mishna states that you can water an irrigation field from a spring, not from a ditch or rain water on chol hamoed. The Talmud explains that it is due to the degree of difficulty. Apparenty shlepping or gathering rain water is more of a burden than obtaining water from a spring.
The Shikker Dovid is not a farmer or an agriculturalist. So what is the differnece from spring water and rain water. The shikker dovid would like to suggest the following: rain is from heaven. It is a gift. One prays for rain. It is unsure or uncertain. The spring is there. It is permanent. The burden of the rain is the uncertaintly, the stress. IT is the shlepping and the stress. On chol hamoed we should have no doubts or burdens, either physical or mental. We should know that hashem will provide. The use of rain water might cause stress. The well is the constant gift of gd. The lesson is that when Chol hamoed comes, we should put aside our normal stress, business burden and rely on our faith in hashem and the moad.