"And He called the twelve together, and gave them power and authority over all the demons and to heal diseases. And He sent them out to proclaim the kingdom of God and to perform healing."
"Now after this the Lord appointed seventy others, and sent them in pairs ahead of Him to every city and place where He Himself was going to come. ... The seventy returned with joy, saying, “Lord, even the demons are subject to us in Your name.”"
Miracles got to be an expectation among the disciples: "When He came into the house, His disciples began questioning Him privately, “Why could we not drive it out?”"
"And he threw the pieces of silver into the temple sanctuary and departed; and he went away and hanged himself."
I wonder what miracles Judas did, and who he paired with for the journey (maybe Matthew?). When you can heal the sick, what's 30 peices of silver more or less? You could get those easily enough (maybe). What would turn you from healer to betrayer?