The Reserve Bank's maintenance of low interest rates is creating the conditions for credit and economic expansion, and the challenge for banks is to respond to these conditions and profit from them.Two years is the low inflation horizon spelled out yesterday by the Reserve Bank of Australia in announcing the monthly decision of its rates meeting.The RBA noted that credit growth was picking up, while the cost of wholesale funding was falling.The market for mortgage-backed securities is firing and is surely open to more widespread use.Lending standards are already showing an innovative bent.So lenders big and small must be poised for a dash for growth."System" will be the cry as banks aim to manage market share, with big banks forced to decide whether to match, lead or lag.If a bothersome world economy can be sidelined, the conditions are ripe for a lot of endeavour on the lending supply side, and for credit growth to step up.