I'm preparing a sermon for Sunday on Mark 1:1-15 and have been immensely helped by James R. Edwards' Pillar commentary on Mark (Apollos, 2002).
It's a sermon I've preached before but am now revisiting and actually changing quite a bit. Edwards wasn't available last time I preached this and I'm glad to have it now.
He's extremely good on the kind of scholarly details that commentaries need to go into - clear without swamping and showing how they are pertinent to Mark's argument, but also steps back in a few places to give the kind of theological comment that helps the preacher and which commentaries often don't give.
On vv.1-15 he stresses the point of the OT prophetic quotations as all clearly related to Jesus' identity and mission, and also gives an excellent treatment of the divine voice at Jesus' baptism: linking issues of kingship, suffering servant, and baptismal identification with sinners, Edwards says things like: 'Jesus is Israel reduced to one'; 'where Israel failed, Jesus takes its place'.