All the friends of God... should contribute to the extent possible

All the friends of God... should contribute to the extent possible, however modest their offering may be. God doth not burden a soul beyond its capacity... O Friends of God! Be ye assured that in place of these contributions, your agriculture, your industry, and your commerce will be blessed by manifold increases, with goodly gifts and bestowals. He who cometh with one goodly deed will receive a tenfold reward. There is no doubt that the living Lord will abundantly confirm those who expend their wealth in His path. 

- 'Abdu'l-Bahá