https://www.newadvent.org/cathen/07256b.htm It means be informed. I appreciate a desire to 'include' like the Apostolic Church I saw that said "Muslims welcome here" but while one of these may attend any particular church, they may not be allowed to affect the orthodoxy of the local church else the local 'church' is no longer 'Christ-honoring' (Christian, orthodox). It means you extended the hand of fellowship to a man, whose heresy Urantia, completely undermines the Cross, Christ, and Salvation. He denies the very means of YOUR salvation, through the blood of Jesus Christ, in fact, he doesn't believe you need saved at all, but that you need to be rather "Urantia" informed.
lain:
Uh huh.
Muslims are welcome at Mass, just as is everybody. Everybody can attend Mass. You can't receive Communion is all, until and unless you convert (or in your case, re-convert through the sacrament of Reconciliation), but you can witness the Mass, and participate, or not participate---Catholics generally don't judge someone who's not standing or kneeling at the appropriate times. You can make the sign of the cross or not. You can genuflect toward the tabernacle or not. You can bow before the altar or not. There's no real rules, and even Communion is distributed to the faithful on the honor system. We are responsible, just as St. Paul instructed the Corinthian diocese, to examine ourselves that we do not receive Communion unworthily, which means that we are not guilty of any un-absolved grave sin.
@Caino is more than welcome at Mass. As are you. And as for "affect the orthodoxy", that's impossible in Catholicism. The Church's magisterium, bolstered immeasurably by Pope St. John Paul II's catechism, is as firm a human footing as can be had w r t orthodoxy, which is the same as teaching on all moral and doctrinal matters that is divine, authoritative, infallible, inerrant and Apostolic. The bishops uniformly teach that which the Apostles uniformly taught, which is Christ's own teaching, which is the Father's own teaching.
I extend the hand of fellowship to Caino because he or she, or neither he nor she, has testified to believing that Jesus is risen from the dead, and the Son of God. According to the aforementioned Catechism, this justified me in seeing him or her, or neither him nor her, as my full and real sibling in Christ, and a fellow member of His Body. The differences in doctrine render us currently imperfectly united, a condition that will remain perhaps until glory, but it is but a temporary state of affairs. I encourage Caino, and you as well, to be received into the Church. Or at least to convert to one of the Orthodox churches, who also do have the sacraments in their fullness, along with the Catholic Church.
Regarding Urantia, or any other thoughts, published or otherwise, when converting to Catholicism, we are asked to confess the Niceno-Napolitano Creed and to renounce Satan. If we can do this with a clear conscience, that is all that is required. If Urantia or anything else that we believe conflicts with the Creed or with renouncing Satan, then we are encouraged to work out our salvation.