Intruder is one who enter inappropriately, especially without invitation or permission and engaged in an activity that deprived others of credit or reward.
This intruder personified as sin entered into this world through Adam.
Rom 5:12 Wherefore, as by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned:
Death by sin started from Adam but lasted at the written law of Moses. This time, death is imputed only after the transgression of the law of Moses.
Rom 5:13 For until the law, sin was in the world: but sin is not imputed when there is no law.
Rom 5:14 Nevertheless, death reigned from Adam to Moses, even over them that had not sinned after the similitude of Adam’s transgression, who is the figure of him that was to come.
At the written law of Moses, sins were taken away by offering sacrifices which were done yearly up to time when the actual sacrificial lamb was offered not yearly but once and for all.
Heb 10:1 For the law having a shadow of good things to come, [and] not the very image of the things, can never with those sacrifices which they offered year by year continually make the comers thereunto perfect.
The law on yearly offering of sacrifices were until Christ death.
Heb 7:27 Who needeth not daily, as those high priests, to offer up sacrifice, first for his own sins, and then for the people’s: for this he did once, when he offered up himself.
But now we are free from the law, having been made dead to that which had power over us; so that we are servants in the new way of the spirit, not in the old way of the letter.
Rom 12:1 I beseech you therefore, brethren, by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable to God, which is your reasonable service.
And put on the new man, to which God has given life, in righteousness and a true and holy way of living.
Rom 2:15 Who show the work of the law written in their hearts, their conscience also bearing testimony, and their thoughts the mean while accusing, or else excusing one another;
Rom 2:16 In the day when God shall judge the secrets of men by Jesus Christ according to my gospel.