In the first reading (Numbers 11:25-29), a disciple of Moses is perturbed that people outside the group are prophesying, but Moses is welcoming.
But Moses answered him,
"Are you jealous for my sake?
Would that all the people of the LORD were prophets!
Would that the LORD might bestow his spirit on them all!"
In the Gospel (Mark 9:38-43, 45, 47-48), a disciple of Christ says “"Teacher, we saw someone driving out demons in your name, and we tried to prevent him because he does not follow us."
"Do not prevent him.
There is no one who performs a mighty deed in my name
who can at the same time speak ill of me.
“For whoever is not against us is for us.”
Of course, in another place (Matthew 12:30), our Lord says,
Whoever is not with me is against me,
and whoever does not gather with me scatters.
There are many important lessons in the tension of these two truths.
One of the things that we should remember is that there are times when we need to work together with others to achieve the common good.
Yet we must also be open-eyed about the different agendas or beliefs of our sometime allies.
Another thing to remember is that God distributes His gifts and His call to holiness universally, yet Jesus Christ is the one and only way to eternal life.