Most of the words and phrases used by Jesus to describe His followers are challenging, encouraging, and positive.
But in Mathew's Gospel Jesus also uses, on five occasions, a less encouraging word for His disciples. He calls them "oligopistoi", which means "of little faith". The word describes an aspect of His disciples' character that Jesus seemed to find downright amazing and quite frustrating. In spite of everything they had seen Jesus do and heard Him say, many times the disciples just "didn't get it". Luke records a conversation Jesus had with two disciples on the Emmaus road after His resurrection in which He describes His followers with another disparaging phrase: "foolish ones and slow of heart to believe." In biblical times the "heart" was considered the source of thought processes, not emotions. (Emotions had their origin in the kidneys). We might translate" slow of heart" to "numbskull". Putting the critical phrases in Matthew and Luke together we get "Foolish numbskull of little faith". I don't know about you, but when I read that I feel like I'm looking in the mirror.
Praise to Jesus, He is patient, and forgiving. God, be merciful to me, a sinner!