Matius 13:13

13:13 For this reason I speak to them in parables: Although they see they do not see, and although they hear they do not hear nor do they understand.

Matius 13:15

13:15 For the heart of this people has become dull;

they are hard of hearing,

and they have shut their eyes,

so that they would not see with their eyes

and hear with their ears

and understand with their hearts

and turn, and I would heal them.’ ¹ 

[13:15]  ¹ sn A quotation from Isa 6:9-10. Thus parables both conceal or reveal depending on whether one is open to hearing what they teach.