The Bible verse for "Whatever you do to the least of my brothers or sisters you do to me" is Matthew 25:40. The full verse reads, according to the New International Version of the Holy Bible, "The King will reply, Truly I tell you, whatever you did for one of the least of these brothers and sisters of mine, you did for me."
The Bible is made up of both the New Testament and the Old Testament. The Old Testament originally was written in Hebrew (translated to many languages) and is used by the Jewish people as well. The New Testament was written about Jesus' life and Jesus' contribution to the faith as the messiah.