The first lesson that I learnt about symbols was that a good symbol has the power to unite people - even when they don't necessarily agree about the meaning of that symbol. Those who know the organisation well can immediately see the significance of this insight to The Salvation Army.
Just this morning I discovered something else: a symbol can be incorruptible. Actually, I don't think that's quite true - but it's pretty close. The intended comparison is with the frailty of human beings: we are corruptible, we fail despite our best intentions, even the best of us eventually perish. Yet some people become symbols that outlast their lives - think Oscar Romero, Martin Luther King, William Booth and of course Jesus!
There's a vital missiological point here: don't let our programs or goals be so tied to the individuals that are running them that the symbol of their purpose is eclipsed. It's also a great reminder about the place of sacrament which joins our common existence with the sacred.