‘But now complete the doing also; that as there was the readiness to will, so there may be the completion also out of your ability. For if the readiness is there, it is acceptable according as a man has, not according as he has not.'
So let them now complete what they had begun. Let them complete ‘the doing' of it, just as they had previously demonstrated that they had the readiness of will to do it. Let their readiness of will result in their finally completing their set task in accordance with their ability to give.
For what is being required is not extreme sacrifice, but a giving on the basis of what can genuinely be afforded. Readiness to give is proved by giving what one can afford, not by giving what one cannot afford. (The latter would indicate sacrificial love like that of the Macedonians, which goes one step further).