I came across the following:-

We, as Christians, tend to complicate our faith.  We use words like ‘sanctification’ when we mean ‘growing’ or ‘substitutionary atonement’ instead of ‘Christ died for us’.

(Rob Wilkins, ‘The profound simplicity of love’, in Willow Creek magazine, January/February 1991)

Can you spot the problem here?  ‘Growing’ does not mean the same as ‘sanctification’.  ‘Growing’ can be predicated of many different things (trees, toe-nails, debts, and so on), whereas as ‘sanctification’ refers specifically to growth in holiness (but is that another ‘complicated’ word that Wilkins thinks we should eschew?).  And ‘Christ died for us’ is not the same as ‘substitutionary atonement’.  ‘Substitutionary atonement’ affirms specifically that Christ died as our ‘substitute’ (in our place), whereas ‘Christ died for us’ is more general, and can mean either (or both) that Christ died in our place, or that he died on our behalf.

So, what you gain in ‘simplicity’ you often lose in precision.  Sometimes, as when speaking to the biblically illiterate, it may be a fair bargain.  But we have no right to go for ‘simplicity’ at all costs.  It is not ‘over-complicating’ the Christian faith to use biblical expressions for biblical concepts (such as ‘sanctification’) or to use non-biblical expressions for biblical concepts (such as ‘substitutionary atonement’, or ‘trinity’).

As someone once said: ‘keep things as simple as possible, but no simpler than that.’

Or, as Oliver Wendell Holmes is reputed to have said, ‘I do not give a fig for the simplicity this side of complexity, but I would give my right arm for the simplicity on the far side of complexity.’