IS THE HYDROCHLORIC ACID PRESENT IN OUR BODY CONCENTRATED ? THEN HOW ARE THE WALLS OF THE STOMACH PROTECTED?

Glands present on the walls of stomach are mainly responsible for the secretion of H⁺ and Cl^- ions, acid thus released is then diluted with the water and other fluids present in the stomach to maintain its pH  between 1 to 3. 
Kindly refer to the following link for details.
https://www.meritnation.com/ask-answer/question/hcl-is-a-corrosive-acid-how-is-the-stomach-protected-from/life-processes/7469845