I’d want to say something like the “Prayer of Humble Access,” because it’s just astoundingly beautiful, but the one I find myself using often in various situations, everything from the beginning of meetings to personal prayer, is the “Collect of Purity.” Beginning my own time of prayer and recollection with the Collect of Purity — like we begin the (Ordinariate) Mass (Divine worship: the Missal) with the Collect of Purity — that’s the one that’s certainly the most familiar and most frequently said, for me.—An excerpt from an interview with Peter Jesserer Smith, National Catholic Register (7-DEC-2016)
The Collect for Purity (CFP) appears in Latin in the 11th-century Leofric Missal and in the Sarum Rite. The CFP was one of the preparatory prayers said by priests before Mass.
Deus cui omne cor patet et omnis voluntas loquitur: et quem nullum latet secretum: purifica per infusionem sancti spiritus cogitationes cordis nostri: ut te perfecte diligere et digne laudare mereamur, per dominum nostrum iesum Christum filium tuum qui tecum vivit et regnat in unitate eiusdem spiritus sancti deus, per omnia secula seculorum. Amen.
The CFP appears as the prologue to The Cloud of Unknowing, a 14th Century treatise on prayer and spirituality.
God, unto Whom alle hertes ben open, and unto Whom alle wille spekith, and unto Whom no privé thing is hid: I beseche Thee so for to clense the entent of myn hert with the unspekable gift of Thi grace that I may parfiteliche love Thee, and worthilich preise Thee. Amen.
The Collect for Purity
Almighty God, unto whom all hearts be open, all desires known, and from whom no secrets are hid: cleanse the thoughts of our hearts by the inspiration of thy Holy Spirit, that we may perfectly love thee, and worthily magnify thy holy Name; through Christ our Lord. Amen.