What is the meaning of "Allah blesses him tenfold" in the Hadith: "Whoever invokes blessings upon me once, Allah blesses him tenfold"?

The hadith in which the Messenger of Allah, peace and blessings be upon him, said: "When you hear the call to prayer (adhan), say what the muezzin says, then invoke blessings upon me, for whoever invokes blessings upon me once, Allah will invoke blessings upon him ten times," is an authentic hadith.

"Invoke blessings upon me" means that the supplicant asks Allah to increase His mercy, praise, and safety upon His Messenger, peace and blessings be upon him. In return, Allah will reward him with mercy, forgiveness, and pleasure. "Allah will invoke blessings upon him ten times" means that Allah grants him ten mercies for each invocation of blessings.