Oratorio is Handel's most outstanding contribution in the history of music. He used the Bible (especially the "Old Testament") as his theme and used English lyrics as lyrics, focusing on composing the story of the enslaved nation's liberation, describing the deeds of the national hero, and praising the nation's victory. After the bourgeois revolution and religious reform, the British audience, especially the general public, was very fond of and familiar with these stories in the Bible. Handel's oratorio can inspire their patriotic enthusiasm and fantasy, and make them have a strong passion.

Handel's oratorios have an epic style. This is expressed through moving arias, dramatic recitatives, grand fugues and double choruses. The most distinctive feature is his use of chorus. He uses the chorus to represent the masses, making them the center of the drama. Handel wrote based on the strong tradition of choral art in the UK, absorbed the experience of German Lutheran choral art and southern German Catholic choral singing, and used his many years of accumulated experience in opera creation to write.

Among his 23 oratorios, "The Israelites in Egypt" (1739), "Messiah" (1742), "Judas Macbeth" (1746), etc. are masterpieces handed down from generation to generation. Among them, "Messiah" was completed in just 24 days. According to the servant's recollection, when he saw Handel finish writing, his eyes were filled with tears and he said: "I seem to have seen the entire heaven and the supreme God with my own eyes!" The lyrics of this work are all selected from the "Bible" and are divided into three parts. It shows the prophecies about the coming of Christ and his birth; the suffering of Christ and the spread of his teachings and the salvation of the world through faith. The music's melodic recitative, broad and smooth arias and majestic chorus embody the typical style of Handel's music. What's more noteworthy is that his band's orchestration is extremely clear and pristine. Mainly strings and continuo, while oboe and bassoon only play a role in strengthening the vocal part; trumpet and timpani are only used under special circumstances. This was the usual practice in the Baroque period, which was to write for a small orchestra, with more people joining in when needed. The orchestration used in some later performances was adapted by later generations (such as Mozart) in order to balance with the growing chorus. In recent years, there has been a tendency to adopt Handel's original style.