And then shall many be offended, and shall betray one another, and shall hate one another (Matthew 24:10).
The word translated offended is the Greek word skandalizo, from which we get the English word scandalize. The word means to put a stumbling block in someone’s path so they will fall; or to entice someone to sin, or fall away. It could also mean to cause a person to begin to distrust and desert one whom he ought to trust and obey.
The Scriptures also state that one could be offended as a result of tribulation or persecution.
But he that received the seed into stony places, the same is he that heareth the word, and anon with joy receiveth it; Yet hath he not root in himself, but dureth for a while: for when tribulation or persecution ariseth because of the word, by and by he is offended. (Matthew 13:20-21)
During the first half of the 70th week of years, Jesus said that many would be offended. He also said that it would be a time of tribulation and persecution. So, it is possible that many would be offended due to the tribulation and persecution.
The night Jesus was betrayed, He told His disciples that they would be offended because of Him.
Then saith Jesus unto them, All ye shall be offended because of me this night: for it is written, I will smite the shepherd, and the sheep of the flock shall be scattered abroad. (Matthew 26:31)
Note that Jesus did not cause the offense, but because of the circumstances surrounding His arrest, the disciples forsook Jesus and fled. This could be the scenario that occurs during the first half of the 70th week of years, which could even possibly lead to some falling away from the faith.
Finally, Jesus had this to say about those who would offend:
But whoso shall offend one of these little ones which believe in me, it were better for him that a millstone were hanged about his neck, and that he were drowned in the depth of the sea.
But whoso shall offend one of these little ones which believe in me, it were better for him that a millstone were hanged about his neck, and [that] he were drowned in the depth of the sea. (Matthew 18:6)