In order to understand the 2 different marks you must understand these 2 different natures and what they detail. First let’s look at these 2 different positions.
Romans 5:19
For as by one man's disobedience many were
made sinners, so by the obedience of one shall many be
made righteous.
The first position is in Adam, where many are made sinners. And if they are made sinners they will do sinful works. This means they are of the world and they are “carnal” being born of the “flesh” and having the “sin nature”of the Devil. This means they are in darkness and are of the evil seed being an evil tree. Those who are still in Adam are marked by sin. This Adam position I will refer to as group A.
The other position we see in Romans 5:19 is in Christ where many shall be made righteous. And if one is made righteous they will also do righteous works. This group is no longer of the world because they have been born again of the Spirit. This group is no longer in the flesh but are in the Spirit, having the Divine nature of Christ. This means they are no longer in the darkness but are now in the Light of Christ. This group are of the good seed and are the good trees. This group are marked by righteousness being made righteous by Christ. This position I will refer to as group C.
Those who are still in position A will try to perform the works of those who are in position C but they cannot because they are still in position A. There is an “enmity” between those in position A against those in position C because of this.
Paul spoke of this enmity and struggle of those in position A trying to do the good works of those in position C in Romans 7.
The reason those in position A could not do the good works of those in position C is because they were still in position A.
But Jesus came to remove that enmity in man, and remove mankind from position A to position C by spiritual rebirth. So those who are truly born again of the Holy Spirit have passed from position A to position C.
Those who are in position C knows what it is like to be in position A. But those in position A do not know what it is like to be in position C. Those in position C try to describe what it is like to be in position C to those who are in position A, but those in position A do not believe them because all position A knows is position A.
The false teachers in position A read about what it is like to be in position C, but they are unable to perform the good works of those in position C. So the false teachers try to blur the lines between the dark position of A from between the Light position of C.
In trying to justify their own position in A they have tried to create a gray area of B between Position A and C.
But there is no gray area, or lukewarm area by which you can be saved. You are either in the A position or in the C position.