Every movement needs an anthem, and Esperanto got its early: Zamenhof's poem of 1890, set to a "triumphal march" by the French composer Félicien Menu de Ménil, and sung at world congresses ever since. When the first Esperanto music records came out in England in 1926, this was on them, twice: once played by a band and once sung.
Grammatically the anthem is a participle museum, and that is its value to a learner finishing the course: - thirsting for blood - is the active -anta participle; and aj are the passive -ita kind; and show -anto making a person out of a verb. And the word esperantoj in the second stanza, "the hoping ones", is the language's own name in the plural. The name came first: Zamenhof had published his first book in 1887 under the pen-name Doktoro Esperanto, "one who hopes", the name stuck to the language, and the 1890 poem echoes it.
Sing the volitive line with intent: - let it fly. The -u ending you learned for commands does the anthem's whole optimism.
The clipped forms - mond', l' espero - are Rule 16 elision, and they follow strict rules of their own: poetic Esperanto walks through exactly what a poet may and may not cut.