Mark 4:26 

Where does the kingdom come from? The Seed. 
What is the seed? The Word

And He said, "The kingdom of God is as if a man should scatter seed on the ground...
Now the parable is this: The seed is the word of God. (Luke 8:11).

Mark 4:28-29

Preacher, Judge Your Success By The Planting, Someone else might be the one harvesting (Paul, Apollos, God)

Mark 4:26-29
No sowing equals NO HARVEST. 
If you do not plant anything, you will have no harvest. If don't sow, you will not reap. 
Reap the hearts of men through the planting of the Gospel.
If You do not sow, you will not have a harvest!

Mark 4:25 
A principle of stewardship. Not everyone will get the same amount. 
Some in the world want equality of possessions, but Jesus denies this principle. 
For whoever has, to him more will be given; but whoever does not have, even what he has will be taken away from him.

Mark 4:24 O be careful little ears what you hear.

Then He said to them, Take heed what you hear. With the same measure you use, it will be measured to you; and to you who hear, more will be given.

Be a good steward of what God has given you in His word.

Mark 4:24 - Take heed what you hear.  

Jesus encourages those who hear Him to judge, to understand, and to measure what they hear.

Then He said to them, Take heed what you hear. With the same measure you use, it will be measured to you; and to you who hear, more will be given.  

Be Careful How You Measure (Mat 7:1)

Now these are the ones sown among thorns; they are the ones who hear the word, and the cares of this world, the deceitfulness of riches, and the desires for other things entering in choke the word, and it becomes unfruitful.  

How crowded is it in your house (and heart)?

Mark 4:18-19 

Mark 4:14 The sower sows the word.  The Right Seed is the Word of God. 

So that Seeing they may see and not perceive, And hearing they may hear and not understand; Lest they should turn, And their sins be forgiven them.

Mark 4:12  - There is a right way to say something.

Mark 4:9

And He said to them, "He who has ears to hear, let him hear!"

Why God gave you Ears… and what you should be doing with them.