Jesus told a man to 'take up his cross' before he had died on the cross

Jesus told a man in Mark 8:34 that "whosoever will come after me,
let him deny himself, take up his cross and follow me." The obvious
question is: What cross? He hadn't yet died on the cross. There was
nothing to take up. That man would have had no idea what he was talking
about.

Biblical Errancy Pamphlets by Dennis McKinsey Pamphlet 2 Q17.

Answer:

(Mark 8:34 NIV) Then he called the crowd to him along with his disciples and said: "If anyone would come after me, he must deny himself and take up his cross and follow me.

Since Israel was under Roman occupation, and crucifixion was the Roman method for carrying out the death penalty, for the common criminal (see Mat 27:28), it is quite reasonable to suppose that the ordinary person would understand what Jesus was saying. A person carrying his cross was carrying it to the place of his own execution. So Jesus was saying that a person had to be prepared to died if he was to follow Jesus.

Two common criminals, Mat 27:28 says thieves, were also crucified with Jesus so Crucifixion was a common sight in Jerusalem.

Luke 23:32 Two other men, both criminals, were also led out with him to be executed.