Or HaChaim on Exodus 23:25/אור החיים על שמות כ״ג:כ״ה

1 ועבדתם את ה׳ אלוקיכם, "and you will serve the Lord your G'd, etc." Perhaps we should understand this verse as related directly to what the Torah wrote in 23,24. If Jews are careful to destroy all remnants of the idolatry practiced by the pagans in the Holy Land the result will be that they will serve the Lord with all their hearts and that G'd will bless them and protect them.

2The Torah writes ואת מימיך, "and your water;" seeing that water is the source of all weakness, carrier of bacteria and origin of most serious diseases, G'd promises that He will ensure that our water will be turned into a source of healthy growth. We all know the importance of מים חיים, i.e. springwater, and man's efforts to reside near the source of such water. For all these reasons G'd's blessing is of such importance here. You may do well to study what the Talmud (Berachot 59) has to say about the quality of the water in the river Euphratus.

3והסרותי מחלה מקרבך. "And I will remove sickness from your midst." G'd characterised the blessing as composed of three components. 1) Man (the Israelites) will be healthy in order to enjoy G'd's bounty. The Torah speaks about: "I will remove sickness," i.e. G'd will do this as an act of providence. Unless there is physical health and wellbeing all food will become repulsive instead of enjoyable. 2) There will not be a woman who miscarries, i.e. nature will co-operate; 3) people will live out their allotted years. In all these matters G'd demonstrated His blessing; without these conditions G'd's usual gifts, i.e. health, food, etc., His blessings would not be recognisable as true blessings.