Hello ,
My mother had this "Serenity Prayer" on a plaque that hung on our living room wall. It wasn't until I became an adult that I really began to deconstruct this famous prayer, and look at it from the eyes of a Christian.
As members of the human race, we often spend so much time thinking about the things that we cannot change. It's a normal part of being a person who journeys here on planet earth, but a great deal of time can be spent on this avenue that often leads us to nowhere.
When we turn over the things that we cannot change to God, He can bring peace that passes all understanding into our hearts, and give us the strength to change those things that we are able to. His love can enable us to do both.
"I can do all things through Christ who strengthens me." Phillipians 4:13
Have a great day and God bless!