Grant: the main verb in this Serenity Prayer. It means give but it also means something more.
When a young person goes to college, he or she may need financial assistance. One form of this assistance is called a grant. With this form of assistance, a need has to be present.
When Reinhold Niebuhr chose the word grant, he must have felt the need of a person finding a new path to walk along, a new outlook, and a new lease on life.
Grants in the temporal sense are usually given to someone who has nothing (land grants). We sometimes have to approach God with nothing in our hands and are also aware of our needs.
We can ask God to grant us things but it is His decision as to whether He, in fact, does give us what we request. Whatever God grants us is according to His will.