Charles H. Spurgeon on Psalms 146:9

He relieveth the fatherless and the widow. The olive tree is not to be twice shaken, the vineyard is not to be twice gathered, nor are the sheaves of corn left in the fields to be gleaned; all that belongs to the poor, to the widow and the orphan. It was allowable to pluck with the hand the ears of corn while passing through a neighbour's field (De 23:25), though a sickle might not be used. The law cares most anxiously for widows and orphans, for "God is a father of the fatherless and a judge of the widows" (Ps 68:5). A widow's raiment might not be taken in pledge, and both widows and orphans were to be invited to their feasts. An institution specially designed for the protection and relief of the poor was the second tithe, the so called poor's tithe. The first tithe belonged to the Levites. What remained over was again tithed, and the produce of this second tithe, devoted in the first two years to a feast in the sanctuary at the offering of firstfruits, was devoted in the third year to a feast in the dwelling house, to which the Levites and the strangers, the widows and the orphans, were invited (De 14:28-29 De 26:12-13). —G. Uhlhorn, in "Christian Charity in the Ancient Church," 1883.