The Gospel of Mark indicates that this inquiry arose when only the twelve and a few intimate followers were near the Lord (Mk. 10), while Matthew does not specify this detail (10), leading one to initially believe that the subsequent answer along with three additional parables were given openly to the entire crowd, until after the fourth parable, when Jesus withdrew to a house (36) and clarified the meaning of the parable concerning the tares in a more private setting with His disciples, eventually sharing three more parables with them alone.
The first part of the Lord's answer to the disciples' question on why He used parables for His teachings indicates that this response was intended solely for the disciples. If one accepts the notion that at this moment, Christ delivered all the parables recorded by Matthew and that this very parable was included, one can envision both the twelve and the Lord's closest companions situated in the boat, allowing for His response to the question to be heard exclusively by them. Following this, He would then share additional parables with the multitude.
The objective of Christ’s parables is primarily to illustrate truths more vividly and clearly using imagery drawn from the visible world or human experiences. In this way, abstract spiritual truths are made perceptible to physical senses and accessible through understanding. The human mind, often preoccupied with earthly concerns and consequently unable to simply ascend to the purely spiritual domain, is gradually guided to a higher understanding through the familiar imagery of parables, as though ascending steps of a ladder. However, Christ's parables serve another purpose, which stands in stark contrast to the first: to obscure truths from those who are unworthy and unable to appreciate or grasp them. Jesus articulated both of these aims regarding His parables. To the disciples’ question about why He spoke to the people in parables, He responded: “To you it is given to know the secrets of the kingdom of heaven, but to them it is not given (Mt. 11). For to them, externally, everything is expressed in parables” (Mk. 11 cf. Lk. 10). He then elucidated why the disciples were afforded the knowledge of the kingdom’s mysteries while the general populace was not, saying: “For whoever has, to him will be given and he will have an abundance, but whoever does not have, even what he thinks he has will be taken away from him” (Mt. 12 cf. Lk. 18). In essence, whoever possesses a genuine longing and capacity to grasp the mysteries of God’s kingdom will find these truths revealed through parables (it will be given), and ultimately, he will receive direct instruction and interpretation (it will be multiplied). Conversely, those lacking this earnest desire, who approach Christ out of mere curiosity or with ulterior motives seeking to twist His teachings, will lose even the semblance of understanding they might think they possess: listening but failing to comprehend the spiritual significance, their knowledge will remain ineffectual, void of impact on their hearts and minds, as mere information without deeper meaning.
To express this insight, Christ referenced a prepositional construct closely related to the circumstances of the rich man and the poor man, applying it to His listeners: “Therefore, I speak to them in parables, because seeing they do not see” (Mt. 13). The rationale for Jesus teaching the crowds in parables lies within the audience itself, in their spiritual blindness, which prevents them from recognizing and understanding His works and teachings in their true essence. Furthermore, citing the prophecy of Isaiah (6:9-10 LXX), Jesus illustrates that this prophecy, while applicable to Isaiah's contemporaries, is wholly realized (ἀναπληροδτα, distinct from κληρούχοι) in the spiritual blindness of His present audience; it also emphasizes that this blindness is self-imposed, as they willingly shut their eyes to God’s works around them. In contrast to these spiritually blind individuals, Christ calls His disciples blessed, affirming that they, with their discerning insight, see and comprehend the reality surrounding them (Mt. 16-17).