The Apostle Paul has been talking about attempting to serve the Lord in the flesh.
In others words, in your own strength.
By the time he gets to the above passages, the sense is that if you attempt to please God in your own strength you won't be able to; you'll have died spiritually - you"ll not have produced spiritual fruit that God will not accept.
If you however put to death the deeds of the flesh through the Spirit - not in your own strength - you shall live.
You will produce spiritual fruit that has life because it is empowered by the Spirit.
See also Galatians 5.
You miss all this in your understanding because you have yet to grasp that the issue Paul is dealing with and addressing, is the issue of Identity.
Identity in Christ given the Believer the moment he or she trusts Christ - see the end of Gal. 2 and into Gal. 3.
What you are doing is looking at things from a lower level of abstraction. The lower level of Behavior - which was what the Law based acceptance before God on, Rom. 10.
See Romans 5 and 6 - the issue is now Identity based behavior.
The issue now is do because you are, not in order to be...
I did not miss anything.
Mat 7:13 Enter ye in at the strait gate: for wide is the gate, and broad is the way, that leadeth to destruction, and many there be which go in thereat:
Mat 7:14 Because strait is the gate, and narrow is the way, which leadeth unto life, and few there be that find it.
Mat 7:15 Beware of false prophets, which come to you in sheep's clothing, but inwardly they are ravening wolves.
Mat 7:16 Ye shall know them by their fruits. Do men gather grapes of thorns, or figs of thistles?
Mat 7:17 Even so every good tree bringeth forth good fruit; but a corrupt tree bringeth forth evil fruit.
Mat 7:18 A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit.
Mat 7:19 Every tree that bringeth not forth good fruit is hewn down, and cast into the fire.
Mat 7:20 Wherefore by their fruits ye shall know them.
Mat 12:33 Either make the tree good, and his fruit good; or else make the tree corrupt, and his fruit corrupt: for the tree is known by his fruit.
Mat 12:34 O generation of vipers, how can ye, being evil, speak good things? for out of the abundance of the heart the mouth speaketh.
Mat 12:35 A good man out of the good treasure of the heart bringeth forth good things: and an evil man out of the evil treasure bringeth forth evil things.
Mat 12:36 But I say unto you, That every idle word that men shall speak, they shall give account thereof in the day of judgment.
Mat 12:37 For by thy words thou shalt be justified, and by thy words thou shalt be condemned.
Note John W and Grosnick Marowbe.
LA