Purpose of parables
From “Tota Scriptura”, Joey Day’s personal Scripture topic index wiki
Purpose of Jesus’ parables
Mt 13:10–17, 34–35; Mk 4:10–13, 33–34; Lk 8:9–10; Jn 12:37–43 (these passages variously cite Ps 78:2; Isa 6:9-10; Isa 53:1)
Parables were often misunderstood
Mt 15:10–20; 16:5–12; Mk 6:52; 7:14–23; 8:14–21; Jn 10:1–6
Literal things were also misunderstood
Mk 9:30–32; Lk 9:43–45