After warning his disciples of coming persecutions in John 15:18-25, Jesus adds in John 16:1:
"All this I have told you so that you will not fall away."

In Matthew 24, Jesus warns us that the future persecutions will be so bad to a point where many will abandon the faith. The reason motivating Jesus in warning the disciples, was to ensure that they would not abandon the faith when resistance and persecution occur.

You see my friend, if we bless a wedding, we have to tell the newly wed couple that not everything is going to be rosy. If you are mentoring someone in business, you have a duty to tell your mentee about the positive and negative aspects of doing business. As preachers, we can tell you about the grace and about the prosperity brought by our Shepherd (ref. Psalms 23:1) but we also have to tell you about the persecutions and offenses that will come along because of your Christian faith.

Even Jesus said:
'“Truly I tell you,” Jesus replied, “no one who has left home or brothers or sisters or mother or father or children or fields for My sake and for the gospel will fail to receive a hundredfold in the present age— houses and brothers and sisters and mothers and children and fields, along with persecutions— and in the age to come, eternal life." (Mark 10:29-30)

Have you noticed that Jesus promises abundance but He also says that the same prosperity will come with persecutions.

Don't be fooled: 'the enemy is not just gonna seat and celebrate when you find your peace and the grace of the Lord. He will work towards troubling you"
In many cases, people quit the faith because they were never told about the battles, the enemy, the persecution, the betrayal and all the negative things that their faith in Christ can attract.
Yes, there is Grace-Peace-Abundance in Christ. But your faith in Christ can also be a cause of persecution.
Do you know what people who quit the faith in Christ often say when persecutions show up?
They say: " I did not sign up for this! I quit!"
They did not sign up for this because nobody told them the full circular truth about Christianity. Those people (the quitters) were too busy listening to selective messages depicting what they wanted they hear.

But if you are warned in advance, you will remain strong in your faith.
If you know, in full conscience, that Jesus warned about persecution, then be kind to everyone. Tell them about the prosperity that Jesus mentioned in Mark 10:30, AND tell them as well about the coming persecutions.

That way, less people will fall away.

The persecution countdown has begun..