to datechon/ho katechon, now we know what was restraining the Antichrist

The Apostle [St. Paul] gives three stages in the evolution of evil: the leaven of iniquity, the great apostasy, and the man of sin. But he adds a clause calculated to determine the time of the main event more accurately; he describes something first as a thing (to datechon), then as a person (ho katechon), preventing the occurrence of the main event: “Only he who now holdeth, do hold, until he be taken out of the way.”
Catholic Encyclopedia > Antichrist

He mentions this in his Second Epistle to the Thessalonians:

2 Thess 2:6-7 (RSVCE)
6 And you know what is restraining him now so that he may be revealed in his time. 7 For the mystery of lawlessness is already at work; only he who now restrains it will do so until he is out of the way.[a]

a. Evil will operate secretly till the final unmasking.

Now that daily Mass has ceased and this is mentioned in prophet Daniel [9:26-27 (RSVCE); continual burnt offering], in hindisght we can now see that it was the Holy Sacrifice of the Mass

to datechon

that was restraining the appearance of the Antichrist.

Luca Signorelli’s 1501 depiction of the antichrist, from the Orvieto Cathedral

Being the ape of God, the devil knows:

Mk 3:27 (RSVCE)
27 But no one can enter a strong man’s house and plunder his goods, unless he first binds the strong man; then indeed he may plunder his house.

With the Holy Mass out of the way, through the agency of his beasts, he can now make war on the saints and conquer them.

The Antichrist is imminent!