Simplify the following text for a Grade 12 native English-speaking person.
Original: The New Testament mentions several resurrection appearances of Jesus on different occasions to his twelve apostles and disciples , including `` more than five hundred brethren at once , '' before Jesus ' Ascension to heaven .
Simplified: The New Testament writes that several times Jesus appeared many times before his Twelve Apostles and disciples , and one time before `` more than five hundred brethren at once , '' before Jesus ' Ascension to heaven .