Jesus spoke of “great faith” and “little faith” and a couple times of “no faith”. But in Luke chapter seventeen, after exhorting His disciples about forgiveness:

“Take heed to yourselves. If your brother sins against you, rebuke him; and if he repents, forgive him. And if he sins against you seven times in a day, and seven times in a day returns to you, saying, ‘I repent,’ you shall forgive him.”

(Luke 17:3,4)

They knew they needed help. They may have thought forgiving this much could be challenging; thus, His exhortation seems to have prompted them to ask for Him to “increase” their faith. In response to their request, He answered:

“If you have faith as a mustard seed, you can say to this mulberry tre ...