XIII. (52) And it came to pass after some days that Cain brought of the fruits of the earth as an offering to the Lord. Here are two accusations against the self-loving man; one that he showed his gratitude to God after some days, and not at once, the other that he made his offering from the fruits, and not from the first fruits, which have a name in one word, the first fruits. Let us now examine into each of these subjects of reproach, and first into that which is first in order, (53) we must do good works, hastening with all speed, and labouring to outstrip others, casting away all slowness and delay. And the best of all good works is the pleasing the first good without any postponement of energy, on which account it is also enjoined, “If thou vowest a vow, thou shalt not delay to perform It.”{25}{#de 23:21.} A vow now is a request for good things addressed to God, and the injunction is, that when one has attained the object of one’s hopes, one must offer offerings of gratitude to God, and not to one’s self, and to offer them if possible without any loss of time, and without any delay; (54) and of those who do not act rightly in this particular, some through forgetfulness of the benefits which they have received, have failed in that great and beautiful virtue of thankfulness, and others form an excessive conceit, have looked upon themselves as the authors of the good things which have befallen them, and have not attributed them to him, who is really the cause of them. A third class are they who commit an offence slighter indeed than the fault of these latter, but more serious than that of the first mentioned, for though they confess that the supreme Ruler is the cause of the good that has befallen them, they still say that they deserved to receive it, for that they are prudent, and courageous, and temperate, and just, so that they may well on these accounts be esteemed by God to be worthy of his favours.