Is the one who contributes a small amount to ongoing charities such as building a mosque, providing water, or relieving distress rewarded, even if he did not pay the full amount?

Allah Almighty is Most Appreciative; He accepts little deeds and rewards them with abundant recompense. He does not let the deed of any doer be lost, no matter how small; as He says: "So whoever does an atom's weight of good will see it," and "And whatever good you spend will be fully repaid to you, and you will not be wronged." Thus, a Muslim is rewarded for whatever they expend, no matter how little, and its reward is stored for them in the Hereafter. Therefore, one should not belittle any good deed they perform, or underestimate any charity they give; rather, they should have good expectations of their Lord. And whoever contributes to building a mosque, even if with a small amount, will have the reward for what they contributed. The more their charity and expenditure increase, the more their reward and recompense increase. The Prophet, peace and blessings be upon him, said: "Whoever builds a mosque for Allah, even if it be like a bird's nest, Allah will build for him a house in Paradise."