It was Edmund Burke who said that all that is necessary for evil to triumph is for good men to do nothing.
Looking back through history, whether on a grand scale or personally, we can all identify occasions when the chance to change things for the better was not taken simply because the assumption was made that someone else would act on our behalf.
One of those occasions could well arise on Friday, when my colleague Michael Moore presents his International Development Assistance Private Member's Bill to the House of Commons for its report stage and third reading.
Reaching the overseas development assistance target of 0.7% of national income and then legislating for it was a commitment boldly stated in each of the three main parties' manifestos and the Coalition Agreement. I am proud that the Liberal Democrats are part of the government which has finally delivered on this 43-year old promise.
We must not forget that our aid is about people. It is very easy to talk financially about aid, the proportion of the budget it commands and the outcomes it must achieve, while ignoring what it has been set up to address.
For the children suffering physical and emotional trauma after fleeing gunfire in the Central African Republic, or the families rebuilding their lives after extensive flooding in Pakistan and Bangladesh, UK aid is a lifeline that helps them start over again.
One week before the Scottish Referendum an astounding 164 MPs from all sides of the House turned up to the Second Reading of Michael Moore's Bill in September, compared to just six who voted against. A significant number of colleagues from both Houses care strongly about development aid and recognise its value. I am sure supportive MPs will stand up and be counted on Friday.
Legislating will mean that the political and public debate shifts away from a focus on how much we spend to the effectiveness of UK aid, so that we can save as many lives as possible. For nurses, doctors and teachers in some of the world's poorest countries, it is imperative to be able to plan service provision for the years to come.