Matthew 16:21 From that time, Jesus began to show his disciples that he must go to Jerusalem and suffer many things from the elders, chief priests, and scribes, and be killed, and the third day be raised up.
Matthew 17:22-23 Now while they were staying in Galilee, Jesus said to them, "The Son of Man is about to be betrayed into the hands of men, and they will kill Him, and the third day He will be raised up." And they were exceedingly sorrowful.
Matthew 20:18-19 Behold, we are going up to Jerusalem, and the Son of Man will be betrayed to the chief priests and to the scribes; and they will condemn Him to death, and deliver Him to the Gentiles to mock and to scourge and to crucify. And the third day He will rise again.
Mark 8:31And He began to teach them that the Son of Man must suffer many things, and be rejected by the elders and chief priests and scribes, and be killed, and after three days rise again.
Mark 9:31-32 For He taught His disciples and said to them, "The Son of Man is being betrayed into the hands of men, and they will kill Him. And after He is killed, He will rise the third day." But they did not understand this saying, and were afraid to ask Him.
Mark 10:33-34 Behold, we are going up to Jerusalem, and the Son of Man will be betrayed to the chief priests and to the scribes; and they will condemn Him to death and deliver Him to the Gentiles; and they will mock Him, and scourge Him, and spit on Him, and kill Him. And the third day He will rise again.
Luke 9:21-22 And He strictly warned and commanded them to tell this to no one, saying, "The Son of Man must suffer many things, and be rejected by the elders and chief priests and scribes, and be killed, and be raised the third day.
Luke 18:31-33 Then He took the twelve aside and said to them, "Behold, we are going up to Jerusalem, and all things that are written by the prophets concerning the Son of Man will be accomplished. For He will be delivered to the Gentiles and will be mocked and insulted and spit upon. They will scourge Him and kill Him. And the third day He will rise again."
Parable of the Wicked Husbandmen (Matthew 21:33-46, Mark 12:1-12, and Luke 20:9-19) says he will be killed in each Synoptic Gospel....
We can also quote numerous prophecies as well saying he will be killed.