how many parts are there in this?
Three.
Messiah (Handel)
The opening soprano solo in E major, "I know that my Redeemer liveth" is one of the few numbers in the oratorio that has remained unrevised from its original form. Its simple unison violin accompaniment and its consoling rhythms apparently brought tears to Burney's eyes. 
the most famous oratorio in the world is messiah written by Composed by George Frideric Handel,with a scriptural text compiled by Charles Jennens. when was this composed? 1741.
wiki:1133792
Messiah (Handel) [SEP] Part III
The opening soprano solo in E major, "I know that my Redeemer liveth" is one of the few numbers in the oratorio that has remained unrevised from its original form. Its simple unison violin accompaniment and its consoling rhythms apparently brought tears to Burney's eyes. It is followed by a quiet chorus that leads to the bass's declamation in D major: "Behold, I tell you a mystery", then the long aria "The trumpet shall sound", marked ' ("dignified but not fast"). Handel originally wrote this in da capo form, but shortened it to dal segno, probably before the first performance.