This last verse of Matt.13:43 referring to those 'who hath ears to hear, let him hear' means this is a private teaching, not everyone will understand. If you do understand, then it's time to start doing some work in our Father's service, because He didn't give It to you for nothing, or just to be entertaining, and let His Truth go to waste. As one of the other parables here in Matt.13 is about those with whom His Word finds fertile soil, they go out and produce good fruit.

 Matt.13:18-23:

18: Hear ye therefore the parable of the sower.

19: When any one heareth the word of the Kingdom, and understandeth not, then come the wicked one, and catcheth away that that which was sown in his heart. This is he which received seed by the way side.

20: But he that received the seed into stony places, the same is he that heareth the word, and anon with joy receiveth it;

21: Yet hath he not root in himself, but dureth for a while: for when tribulation or persecution ariseth because of the word, by and by he is offended.

22: He also that received seed among the thorns is he that heareth the word: and the care of this world, and the deceitfulness of riches, choke the word, and he becometh unfruitful.

23: But he that received seed into the good ground is he that heareth the word, and understandeth it; which also beareth fruit, and bringeth forth, some an hundredfold, some sixty, some thirty.

       Let's continue back in Genesis:

Gen 3:16. Unto the woman He said, "I will greatly multiply thy sorrow and thy conception; in sorrow thou shalt bring forth children; and thy desire shall be to thy husband, and he shall rule over thee."
17    And unto Adam He said, "Because thou hast hearkened unto the voice of thy wife, and hast eaten of the tree, of which I commanded thee, saying, 'Thou shalt not eat of it:' cursed is the ground for thy sake; in sorrow shalt thou eat of it all the days of thy life;
18    Thorns also and thistles shall it bring forth to thee; and thou shalt eat the herb of the field;
19    In the sweat of thy face shalt thou eat bread, till thou return unto the ground; for out of it wast thou taken: for dust thou art, and unto dust shalt thou return."

     No more easy living in the Garden for Adam and Eve. Paradise is over. No more simple 'sheep' existence with plenty of leisure and food. The 'sheep' now become lost in a sense, for they have lost their Good Shepherd, i.e., God. That old flesh body is going back to dust when we put off this flesh, dust meaning into particles. It's not going to be put back together, for the spiritual body is what leaves that old flesh .

 

I Cor.15:  3 Christ’s resurrection, 12 he proveth the necessity of our resurrection, against all such as deny the resurrection of the body.  21 The fruit, 35 and manner thereof, 51 and of the changing of them, that shall be found alive at the last day.

 

Eccl.12:  1 The Creator is to be remembered in due time. 8 The preacher’s care to edify. 13 The fear of god is the chief antidote of vanity.

Eccl 12:7: Then shall the dust return to the earth as it was: and the spirit shall return unto God who gave it.