I like Apostle Jack's answer to his own question - God, Christ and the New Covenant (all things divine) are all based on the Holy Spirit and are invisilbe spiritual elements.
I do not however, frown upon the use of "iconography", as these things should be treated no more severly than like a club or business having a "logo" to which they identify who they are (like with Christians and the "fish" or Jews and the "Star of David" on their flag). Just be careful how you reflect on the same and to what degree of respect or priority you place on it in your life.
I likewise also acknowledge the difference between a symbol being used for the purpose of identification and its elevation to the point of almost becoming IDOLATRY. This is truly the difference and intent we should be concerned with; for example, the use of statues or icons (even the cross) to represent historical things in the church, but which are then given honor and tribute. The "cross" for example should only be thought of and reflect as a reminder of what actually transpired ON the cross itself (the event) and not become an object that is elevated to praise or acknowlegement in any other form. Therein likes the real danger to our souls when that distinction inadvertantly crosses the line into the equivalent of idolatry (even if doing so indirectly, accidentally or out of ignorance).