John 14:5
Thomas saith unto Him, Lord, we know not whither thou art going, and how can we know the way?
John 11:16
Thomas therefore, who is called Didymus, said to his fellow-disciples, Let us also go, that we may die with him.
Mark 8:17-18
And Jesus knowing it saith unto them, What are ye reasoning about? because ye have no bread? Do ye not yet discern nor understand? have ye your heart still hardened?
Mark 9:19
And He answered and said, O unbelieving generation, how long shall I be with you? how long shall I bear with you? bring him to me.
Luke 24:25
And He said unto them, O people void of understanding and slow of heart to believe all that the prophets have spoken.
John 15:12
This is my commandment, that ye love one another, as I have loved you.
John 20:25-28
The other disciples therefore told him, We have seen the Lord. But he said unto them, Except I see in his hands the mark of the nails, and put my finger into the place of the nails, and my hand into his side, I will not believe.
Hebrews 5:11-12
Concerning whom we have much to say and difficult to be explained, since ye are become dull of hearing.