Let us therefore serve God with a pure heart, and we shall be righteous; but if we do not serve Him, because we believe not the promise of God, we shall be miserable. For the prophetic word also declares, "Wretched are those of a double mind, and who doubt in their heart, who say, All these things have we heard even in the times of our fathers; but though we have waited day by day, we have seen none of them accomplished. Ye fools! compare yourselves to a tree; take, for instance, the vine. First of all it sheds its leaves, then the bud appears; after that the sour grape, and then the fully-ripened fruit. So, likewise, my people have borne disturbances and afflictions, but afterwards shall they receive their good things." [3923] Wherefore, my brethren, let us not be of a double mind, but let us hope and endure, that we also may obtain the reward. For He is faithful who has promised that He will bestow on every one a reward according to his works. If, therefore, we shall do righteousness in the sight of God, we shall enter into His kingdom, and shall receive the promises, "which ear hath not heard, nor eye seen, neither have entered into the heart of man." [3924]