Jesus was teaching them the word with such parables, so that they could listen.
This verse shows the adapted wisdom of Christ’s teaching. He spoke to them in a way they were able to hear. This does not mean that the truth was changing, but that the Lord was giving it according to people’s capacity and readiness. Biblical revelation is often gradual. A person cannot at once bear the whole light if the heart is not yet ready. Christ’s words were full of perfect truth, yet He communicated them in such a way that the listener could receive them to some extent and then gradually go deeper. This is a great lesson for teaching in general as well. The truth must be made known in a faithful way, but also with wisdom, taking into account the condition of the heart.