OUTLINE:

Unbelievers
The basic reason why someone rejects the Gospel is because its foundational premise is that they realize that a person NEEDS a Savior! If a person never rightly reconciles the chasm between themselves and the sovereign God of the Universe, they will miss this point altogether. There's a very real impetus for salvation.

Evil Has a Champion
Satan's ploy is to get people believing they are righteous without God's help...or at least "enough" to gain entrance into Heaven (even the end goal is perverted). He propagates lies stating that if you're self-righteous enough, you certainly don't need Christ-righteousness.

Mt 13 - The "Key" Parables
Ask yourself, after reading through Mt 13 all at once without stopping/pondering doctrines, what the nature of Jesus' parables were. Think big-picture, and think simple. HINT: consider membership, not membership types.

The Gospel Hope
The Gospel is EVERYTHING to a believer. Any hope of deliverance at or after being saved is a function of this one reality.

"if you hold fast the word"
Paul was concerned about the quality of what people believed in, and whether or not said belief resulted in true faith (2Co 13:5; 1Jn 2:19). "For by grace you have been saved through faith" (Eph 2:8a). The Gospel of salvation was the centerpiece of his ministry, always.

2Co 13:5 [Amplified]
Test and evaluate yourselves to see whether you are in the faith and living your lives as [committed] believers. Examine yourselves [not me]! Or do you not recognize this about yourselves [by an ongoing experience] that Jesus Christ is in you-unless indeed you fail the test and are rejected as counterfeit?

"if you hold fast the word"
Paul was concerned about the quality of what people believed in, and whether or not said belief resulted in true faith (2Co 13:5; 1Jn 2:19). "For by grace you have been saved through faith" (Eph 2:8a). The Gospel of salvation was the centerpiece of his ministry, always.

"first importance"
from protos - implies a superlative; means foremost (in time, place, order of importance); in context, places the Gospel as the centerpiece of Paul's ministry

"and so you believed"
This is the very reason, the intended result, of Paul's preaching. This wasn't some diatribe against Corinthian immaturity, it was a clear indication of the goal of Paul's ministry - "to seek and to save" (ala Lk 19:10).

Jesus NEVER had a problem challenging a person's salvation.

Mt 12:32
"Whoever speaks a word against the Son of Man, it shall be forgiven him; but whoever speaks against the Holy Spirit, it shall not be forgiven him, either in this age or in the age to come."

1Th 5:21-22 [Amplified]
But test and prove all things [until you can recognize] what is good; [to that] hold fast. Abstain from evil [shrink from it and keep aloof from it] in whatever form or whatever kind it may be.

"examine everything carefully"
Never take anyone's word at face value. Examine the things you hear from fellow man carefully, lest you be lazy and accept false doctrines as truth. "A man who stands for nothing falls for anything."

Jn 8:32
"and you will know the truth, and the truth will make you free."

A Shepherd's Heart
A true shepherd is not interested in his sheep doing anything except following his God-given ability to lead them to Truth. The act of believing Holy Scripture is an issue between a sheep and the Great Shepherd, Jesus Christ. (Ac 17:10-12)

Jesus Chose His Apostles
As a function of His praying, Jesus never made a mistake in choosing the apostles. Even Judas Iscariot was a choice He made at the behest of His Father in Heaven.

"By Grace, They Were Prepared"
Not only did their natural abilities have nothing to do with Jesus choosing them; but they had nothing to do with their preparation for ministry. In fact, their natural "abilities" handicapped them.

Sending the Apostles Out
• Jesus called them
• Jesus trained them (academically & OJT)
• Jesus sent them out

"By Grace, They Were Prepared"
We need to understand when/how the apostles' natural abilities were insufficient for the commission they were eventually given. It wasn't enough that Jesus simply called 12 "unexceptional" men. He made a point of training them up before sending them out.

"you lay aside"
aorist tense (one-time, once and for all) middle voice (subject does and receives the action) indicative mood (dogmatic fact) - means to lay off or aside, renounce, stow away; in context, refers to what a true believer does.

The Implications of "you lay aside"
• Aorist Tense: a believer lays aside the old self forever
• Middle Voice: a believer is changed and therefore forever able to do so
• Indicative Mood: the above are dogmatic statements of fact

"put on the new self"
aorist-middle-infinitive (corresponds to "you lay aside" v22) - means to don, or put on (as clothing); in context, implies the "other side of the same coin", that is "you lay aside the old self", that occurs at salvation and forevermore.
God's grace never fails!