This short passage of story we had before in Mark. It is thus recorded twice, to teach us, 1. That charity to the poor is a main matter in religion. Our Lord Jesus took all occasions to commend it and recommend it. He had just mentioned the barbarity of the scribes, who devoured poor widows (ch. 20); and perhaps this is designed as an aggravation of it, that the poor widows were the best benefactors to the public funds, of which the scribes had the disposal. 2. That Jesus Christ has his eye upon us, to observe what we give to the poor, and what we contribute to works of piety and charity. Christ, though intent upon his preaching, looked up, to see what gifts were cast into the treasury, Luk 21:1. He observes whether we give largely and liberally, in proportion to what we have, or whether we be sneaking and paltry in it; nay, his eye goes further, he observes whether we give charitably and with a willing mind, or grudgingly and with reluctance. This should make us afraid of coming short of our duty in this matter; men may be deceived with excuses which Christ knows to be frivolous. And this should encourage us to be abundant in it, without desiring that men should know it; it is enough that Christ does; he sees in secret, and will reward openly. 3. That Christ observes and accepts the charity of the poor in a particular manner. Those that have nothing to give may yet do a great deal in charity by ministering to the poor, and helping them, and begging for them, that cannot help themselves, or beg for themselves. But here was one that was herself poor and yet gave what little she had to the treasury. It was but two mites, which make a farthing; but Christ magnified it as a piece of charity exceeding all the rest: She has cast in more than they all. Christ does not blame her for indiscretion, in giving what she wanted herself, nor for vanity in giving among the rich to the treasury; but commended her liberality, and her willingness to part with what little she had for the glory of God, which proceeded from a belief of and dependence upon God's providence to take care of her. Jehovah-jireh - the Lord will provide. 4. That, whatever may be called the offerings of God, we ought to have a respect for, and to our power, yea, and beyond our power, to contribute cheerfully to. These have cast in unto the offerings of God. What is given to the support of the ministry and the gospel, to the spreading and propagating of religion, the education of youth, the release of prisoners, the relief of widows and strangers, and the maintenance of poor families, is given to the offerings of God, and it shall be so accepted and recompensed.

The rich men casting their gifts into the treasury - See all this, from Luk 21:1-4, explained on Mar 12:41-44 (note).