Verses 11 to 16 of John 11. 

Then he said, “Our friend Lazarus has fallen asleep, but now I will go and wake him up.”

The disciples said, “Lord, if he is sleeping, he will soon get better!” They thought Jesus meant Lazarus was simply sleeping, but Jesus meant Lazarus had died. So he told them plainly, “Lazarus is dead. And for your sakes, I’m glad I wasn’t there, for now you will really believe. Come, let’s go see him.” Thomas, nicknamed the Twin, said to his fellow disciples, “Let’s go, too—and die with Jesus.”