Today I'm reading around my topic for Sunday, the last in our parables series, 'stories Jesus told about prayer.' I saw these and they seemed worth sharing:
Intercession is work for others. It is an act of faith in God, his caring, his goodness. It is involved in the mystery of God and the freedom of man (sic). We intercede for others because of what we believe about God as loving Father, who works directly, but also through men and women, using their cooperation. Intercession depends on th elife of faith, not on words. We intercede with out whol being, opening a door for God, becomign channels, bringing people to God as Aaron did (Ex. 28.29). We can do this by name in a list, on request, because we aware of need. We can cover all persons and subjects. Results are only sometimes known, and all intercessions implies: 'Not my will, but thine, be done.'
And on the difference between intercession (prayer for others) and petition (prayer for self)
The distinction between petition and intercession - which is petition for others - is not always easy to draw. But the two should be kept separate. Petition concerns our straight course to God; intercession our placing of oursleves between him and the world.
Both from SCM A Dictionary of Christian Spirituality
Taking the two together, then, intercession has a pontifical (bridge) or priestly function, which sits well with understandings of the 'priesthood of all believers' which is why it is so important in public worship.