John 11:13

13 Jesus had been speaking of his death, but his disciples thought he meant natural sleep.

John 11:13 in Other Translations

13 Howbeit Jesus spake of his death: but they thought that he had spoken of taking of rest in sleep.

13 Now Jesus had spoken of his death, but they thought that he meant taking rest in sleep.

13 They thought Jesus meant Lazarus was simply sleeping, but Jesus meant Lazarus had died.

13 Jesus was talking about death, while his disciples thought he was talking about taking a nap.

13 Jesus, however, was speaking about his death, but they thought He was speaking about natural sleep.

John 11:13

Howbeit Jesus spake of his death
Under the figurative phrase of sleeping:

but they thought that he had spoken of taking of rest in sleep;
in a literal and natural sense.

Taken from John Gill's Exposition of the Bible

11 After he had said this, he went on to tell them, “Our friend Lazarus has fallen asleep; but I am going there to wake him up.”

12 His disciples replied, “Lord, if he sleeps, he will get better.”

13 Jesus had been speaking of his death, but his disciples thought he meant natural sleep.

14 So then he told them plainly, “Lazarus is dead,

15 and for your sake I am glad I was not there, so that you may believe. But let us go to him.”