John 14:5
"Lord," said Thomas, "we do not know where you are going, and how are we to know the way?"
John 11:16
Whereupon Thomas (called 'the Twin') said to his fellow-disciples, "Let us go too, let us die along with him!"
Mark 8:17-18
He noted this and said to them, "Why do you argue you have no bread? Do you not see, do you not understand, even yet? Are you still dull of heart?
Mark 9:19
He answered them, "O faithless generation, how long must I still be with you? how long have I to bear with you? Bring him to me."
Luke 24:25
He said to them, "O foolish men, with hearts so slow to believe, after all the prophets have declared!
John 15:12
This is my command: you are to love one another as I have loved you.
John 20:25-28
and when the rest of the disciples told him, "We have seen the Lord," he said, "Unless I see his hands with the mark of the nails, and put my finger where the nails were, and put my hand into his side, I refuse to believe it."
Hebrews 5:11-12
On this point I have a great deal to say, which it is hard to make intelligible to you. For you have grown dull of hearing.