Sure, simple enough.
The entire point of taxation and the multiplier effect, as per Keynesianomics, is that the government has a marginal propernsity to consume higher than that of consumers. In other words, while consumers may save, governments immediately spend their money. In fact, governments almost always run permanent deficits. In other words, if we were to assume that consumption leads to inflation, then government spending their tax money would be even more inflationary.
However, the more fundamental issue at hand is that consumption does not lead to inflation in a free-market. This is because any rise in conumption is met by a rise in supply. Draw a supply/demand diagram. Then draw expanding demand. Then realise that at higher price levels, businesses will find it more profitable to produce, and will expand supply by as much, to reach a new equilibrium with the same price as before, but higher quantity supplied, in other words economic growth. What’s more, is entrepeneurs are in the business of anticipating demand, so it seems quite natural that they may see it in advance.
Thirdly, an increase in the demand for one good can only come about as compensating for a decrease in the demand for another good, in other words, there is no net change, and while one good’s price may be temorarily increased, the other’s will fall, and no inflation will occur. Of course, the other option is that consumption will increase at the expense of savings, in other words, the time preference will have risen, but at that point in time the savings will fall, causing interest rates to rise, and so the savings will once again rebound to their previous level, and time preferences will be restored, if nothing else changes.
Of course, this only applies to an unhampered market. The current bout of interventionism usually leads to this mechanism not functioning, for example interest rates are not determined by the time preference, but rather by a central bank’s “monetary policy”, which can never properly gauge time preferences.
I hope I didn’t overcomplicate the third point, but you should understand the first two points without trouble.