Mat 5:5 Blessed are the meek: for they shall inherit the earth.
Wealthy [are] the gentle ones because they are going to take possession of the planet.
As we have seen in the last two verses, the word translated as "blessed" has many different meanings including "wealthy." It takes these meaning from the larger context. In Mat 5:3, it gets the sense of "wealthy" as a contrary meaning to "poor." Here, Christ switches things up. Giving it the meaning of "wealthy" directly from the idea of taking possession of something.
"The meek" is an adjective used as a noun that primarily "gentle" and "soft." It was also a word for "tame." A bridle is called by this term, so a "tamer". However, as a noun (as it is used here) it is used as a term of endearment (i.e. "gentle one") and to describe a caress. Christ uses this attribute to describe "softness" in the sense of being pliable and adaptable with the sense of being able to learn. Learning is another way of taming. The other place Christ uses this word is Mat 11:29 where he applies it to himself in the specific context of "learn from me."
The "for" here is a causal adverb that means "seeing that", "because", or "since."
The "they" is used explicitly as the subject of the final phrase. This is unnecessary in Greek because the subject is also a part of the verb ending. Christ only uses the pronoun when he wants to emphasize it.
The word translated as "inherit," means both to be and heir and to leave an heir behind. However, more generally, it means "to acquire," and "to take possession of something."
The word translated as "the earth" is the word that Christ uses to describe the physical planet, but it also means land and dirt. In other words, it is like our word, earth.
There are a number of patterns in the Beatitudes, which are discussed in this article, The Beatitudes.
A play on opposing meaning of "meek" meaning both those who are tamed and those who tame. Implying the sense of lucky as "wealthy" from the context of inheritance.
The Spoken Version:
A group of children pressed toward him, their parents trailing behind. A little girl dashed out and held her arms toward the speaker to be picked up. The speaker obliged with a smiling nod to her parents who were trying to catch her.
“Lucky!” He announced once more. “The malleable ones!” He held up the child for the crowd to see. “Because they themselves are going to inherit—,” He paused as he moved toward the child’s parents.
“The realm of the skies?” Several in the crowd suggested.
He smiled, shook his head, no. He put the child in the arms of her mother.
“The earth!” He said, spreading his arms wide to indicate the lands around them.
“οἱ πραεῖς,” (adj pl masc nom) "Meek" is from praus, which means "mild", "soft", "gentle", "meek", "making mild," and "taming." As and adverb, "mildly" and "gently." It describes both animals that are tame and those who tame them. When addressed to an individual (i.e. "gentle one") it is a term of affection. When applied to an action, it describes a "caress."
αὐτοὶ (adj pl masc/fem nom) "They" is from autos, which means "the same," and the reflexive pronouns, "myself", "yourself", "himself", "herself", "itself," or the oblique case of the pronouns, "him", "her," and "it." It also means "one's true self," that is, "the soul" as opposed to the body and "of ones own accord."