Augustine on Psalm CIX
ALMIGHTY and everlasting God, who art always more ready to hear than we to pray, and art wont to give more than either we desire or deserve; Pour down upon us the abundance of thy mercy; forgiving us those things whereof our conscience is afraid, and giving unto us that that our prayer dare not presume to ask, through Jesus Christ our Lord. Amen.
Source of Collect: Leo , revised by Gelasius . (An 1662 revision by Bishop Cosin added and giving us those good things which we are not worthy to ask, but through the merits and mediation of Jesus Christ, thy Son, our Lord. [Barbee and Zahl]
Augustine wrote of this psalm,
Every one who faithfully readeth the Acts of the Apostles, acknowledgeth that this Psalm containeth a prophecy of Christ; for it evidently appeareth that what is here written, "let his days be few, and let another take his office," is prophesied of Judas, the betrayer of Christ....For as some things are said which seem peculiarly to apply to the Apostle Peter, and yet are not clear in their meaning, unless when referred to the Church, whom he is acknowledged to have figuratively represented, on account of the primacy  which he bore among the Disciples; as it is written, "I will give unto thee the keys of the kingdom of heaven," and other passages of the like purport: so Judas doth represent those Jews who were enemies of Christ, who both then hated Christ, and now, in their line of succession, this species of wickedness continuing, hate Him. Of these men, and of this people, not only may what we read more openly discovered in this Psalm be conveniently understood, but also those things which are more expressly stated concerning Judas himself.
Augustine followed a rule of faith in approaching Scripture. Another rule was related to me this day by my friend in a book review of The Word of God for the People of God where he wrote:,
As Billings points out, the rule of faith, specifically as it is laid out in a tool like the Apostles' Creed, is overtly Trinitarian, announcing how God was active in Jesus Christ. Embracing this rule of faith in reading Scripture gives us the Jesus-authorized (Luke 24) go-ahead to appropriate the Old Testament in such a Jesus-shaped way that "Christians do not receive the Old Testament as a generic "word from God" to be received apart from Christ; it is because of Christ that Christians read the Old Testament as Scripture at all. […] Christians receive Israel's Scripture as their own because of "the new covenant made by God in Christ," into which they are grafted by God's covenant with Abraham" (168).
Released by Primus Pilus
Legio Christi-Ecclesia Militans
"Let us therefore follow after the things which make for peace, and things wherewith one may edify another" [St. Paul's Epistle to the Romans 14:19]
* ORDO CENTURIONUM * IN HOC SIGNO VINCES * TIME DEUM ET OPERARE IUSTITIAM