Precisely so. That's what Jesus said. Note well, Jesus said that in the context of people attacking him for the healing miracles he performed. They said that he was performing major healing miracles by the power of Satan.
He replied to that accusation with that very question: "Can Satan cast out Satan?"
Then answered, as you did, in the negative. And then, right then, right there, he spoke of the unforgiveable sin: ascribing the works of God, of the Holy Spirit to Satan. The works to which he was specifically referring at that moment, that he was defending, was his works of major healing.
And THAT is the problem with Lourdes. God has restored sight to the blind at Lourdes, paralytics have stood up and walked out of the waters. These are medical facts, and they present a terrible problem for those who would attack the miracles because they occur specifically at a place where Mary appeared in the 1800s, and where a shrine was built dedicated to her - Our Lady of Lourdes.
God is performing major miracles there, at a Marian site, before the eyes of the world - the very sort of miracles that Jesus performed, of that magnitude. And you have people up this very thread attacking those very miracles as Satanic deceptions, just EXACTLY like the Pharisees and scribes attacked Jesus for performing the same miracles.
Jesus rounded on them and told them that Satan cannot cast out Satan, and to ascribe such things, done by the power of the Holy Spirit, to the power of Satan was an unforgiveable sin.
I understand very well why some people have a terrible, terrible time with major divine miracles happening at a Marian shrine - Mary's role as emissary is not in the Bible. It is easy, then, to simply ascribe all miracles that happen in a place devoted to Mary as satanic, because one refuses to accept that there can be any revelation outside of the Bible.
The PROBLEM with that approach is that it is literally committing the unpardonable sins: it is taking the SAME miracles that Jesus performed, and that Jesus said Satan CAN'T perform, and ascribing them to Satan, thereby blaspheming the Holy Spirit, and doing so for the same reason that the Pharisees did the same way: God came in a way that was NOT EXPECTED, and NOT CLEARLY DESCRIBED in the Scriptures before. The Pharisees were reading the Scriptures and knew them, and NOWHERE did those Scriptures tell them that God would have a biological son, who would be poor and perform major miracles. Their whole tradition was challenged by Jesus, SO they ascribed his healing miracles to Satan.
Now page up this thread and look at the essay written to me which ascribed the major healing miracles at the Marian shrine at Lourdes to Satan.
And realize that my question: "Can Satan cast out Satan?" is Jesus' own question, to the identical challenge in the identical specific circumstance: major healing miracles that Satan cannot perform, and note well that the next thing that Jesus said was that to ascribe those things to Satan was to blaspheme the Holy Spirit and would not be forgiven.
THAT IS THE PROBLEM WITH THE LOURDES HEALINGS.
They are REAL and scientifically documented for over a century.
There are a lot of them. Hosptials all combined do not have the spontaneous reversal of blindness, things like that, with the regularity and in the numbers that Lourdes does. Real major miracles, in probability curve breaking numbers.
They are of a nature that medicine can't do them, but that Jesus did.
And Jesus said that Satan can't do those things.
So, who did them? God.
Where? Not everywhere. There's no OTHER Lourdes. There's only Lourdes.
And Lourdes is a shrine that was specifically built at a site of a Marian visitation.
Lourdes is a new divine revelation of the particular importance of Mary. It is post-Biblical, but the nature of the miracles are divine. To call them Satanic is to blaspheme the Holy Spirit who did them.
Faced with Lourdes, Sola Scriptura will not help you. You have to deal with it. To deny the miracles is to lie.
To ascribe them to Satan is to blaspheme the Holy Spirit, because Satan cannot cast out Satan, and healing the blind is a Jesus-level miracle.
That's the problem with Lourdes. It is a visible statement by God of the approval of Mary as his emissary, and a beacon to everybody that there is, in fact, major divine revelation going on TODAY, which means that the Bible is not the complete story. There is MORE, and it's still going on - and MARY, specifically Mary - is the emissary that God has used to deliver these messages. The MesoAmericans converted en masse because Mary visited.
Are we to worship Mary? No. BUT we are not to DENY the reality of Mary's divine mission either.
In short, Lourdes and Guadelupe are the concrete refutation of Sola Scriptura: because they're real, they're really divine, they're miraculous, and there's not a whisper about them in the Bible.
But there is the warning from Jesus not to ascribe major healing miracles to Satan - that is the unpardonable sin.