Because of their lack of faith 

“But Jesus said to them, ‘A prophet is not without honor except in his native place and in his own house.’ And he did not work many mighty deeds there because of their lack of faith.” (MT 13: 57-58) 

Almighty God is limited in His power by our faith—a paradox of our nature created by God, who fights for our hearts only through love. He needs our faith, our trust and our love to make miracles in our lives. He can’t save us without us. 

“The word of the Lord remains forever; this is the word that has been proclaimed to you.” (Gospel Acclamation)