Shared ground
Mark 3:13–15 presents Jesus as the initiator of a deliberate, organized mission. He withdraws to a mountain, summons specific people “he wanted,” and they come to him. The group is not self-selected; the text highlights Jesus’ choice and call.
Jesus then “appoints” a defined number—twelve—marking them as a recognized core. Two purposes are stated explicitly: (1) relationship and formation (“to be with him”), and (2) deployment (“to send them out”). Their sending is not vague. It is described as public announcing (“to preach”) and as acting with delegated authority—specifically in healing sickness and casting out demons.
Where interpretation differs
Some readers take the “mountain” mainly as a practical setting (space away from crowds), while others hear a deliberate “big-moment” signal—Mark framing this appointment as weighty and memorable.
Some also differ on how broad the Twelve’s “authority” is. One view reads it as limited to particular mission assignments; another reads it as a lasting role that continues beyond a single trip. The text itself states they “have authority” connected to being “sent out,” but it does not spell out duration.
Why the disagreement exists
Mark gives short, compact statements without explaining symbolism (“mountain”), without defining the content of “preach,” and without clarifying whether the authority is temporary or permanent. Later passages can be used to fill in those gaps, but this unit alone leaves them open.
What this passage clearly contributes
This passage clearly ties mission to presence with Jesus: being “with him” is listed before being “sent out.” It also shows that preaching and spiritual/physical deliverance are portrayed as part of the same delegated mission. Finally, it introduces “the Twelve” as a purposeful, numbered group, implying coordination and representation rather than an informal crowd.