What is the requirement to be His audience? Back then, Jesus already declares: “Anyone with ears to hear should listen and understand.”
Is it too difficult to understand? The answer is no, unless the person has no ear (physically impaired in hearing). Today we have effective hearing aids to hear. And we have many easily accessible and understandable ways to hear Jesus.
The conclusion: everyone should be able to hear and understand what Jesus is saying. It has thus become a matter of choice and responsibility on the part of the ‘audience’ to either accept or decline the invitation from Jesus to hear Him and understand Him.
Mark 4 New Living Translation (NLT) (quoted in parts; highlight added)
Parable of the Farmer Scattering Seed
Once again Jesus began teaching by the lakeshore. A very large crowd soon gathered around him, so he got into a boat. Then he sat in the boat while all the people remained on the shore. 2 He taught them by telling many stories in the form of parables, such as this one:…
3 “Listen! A farmer went out to plant some seed…
9 Then he said, “Anyone with ears to hear should listen and understand.”
10 Later, when Jesus was alone with the twelve disciples and with the others who were gathered around, they asked him what the parables meant.
11 He replied, “You are permitted to understand the secret[a] of the Kingdom of God. But I use parables for everything I say to outsiders, 12 so that the Scriptures might be fulfilled:
13 Then Jesus said to them, “If you can’t understand the meaning of this parable, how will you understand all the other parables?…
20 And the seed that fell on good soil represents those who hear and accept God’s word and produce a harvest of thirty, sixty, or even a hundred times as much as had been planted!”
Parable of the Lamp
21 Then Jesus asked them, “Would anyone light a lamp and then put it under a basket or under a bed?….
23 Anyone with ears to hear should listen and understand.”
24 Then he added, “Pay close attention to what you hear. The closer you listen, the more understanding you will be given[c]—and you will receive even more. 25 To those who listen to my teaching, more understanding will be given. But for those who are not listening, even what little understanding they have will be taken away from them.”
Parable of the Growing Seed
26 Jesus also said, “The Kingdom of God is like a farmer who scatters seed on the ground…
30 Jesus said, “How can I describe the Kingdom of God? What story should I use to illustrate it?…
33 Jesus used many similar stories and illustrations to teach the people as much as they could understand. 34 In fact, in his public ministry he never taught without using parables; but afterward, when he was alone with his disciples, he explained everything to them.
Jesus Calms the Storm
35 As evening came, Jesus said to his disciples, “Let’s cross to the other side of the lake.”…
39 When Jesus woke up, he rebuked the wind and said to the waves, “Silence! Be still!” Suddenly the wind stopped, and there was a great calm. 40 Then he asked them, “Why are you afraid? Do you still have no faith?”