'It is I' in the Bible

Just then Jesus called out to them, "Take courage and do not be afraid; it is I."

For what benefit is it to a person if he gains the whole world [of material things] but [has to] give up his life [i.e., all the spiritual blessings]? Or what should a person give in exchange for his life?

"It will be too bad for the world because of occasions that cause people to fall away [from God]! For it is inevitable that such occasions come, but it is too bad for that person who is responsible for causing it to happen.