Psalm 53 v2 - Why do we need to keep asking?

At first glance the two phrases of verse 2 of Psalm 53 seem to say the same thing, using words frequently repeated in the psalter.  

The Fathers and Theologians though, drew out several important nuances in its wording, including the distinction between making our plea, and it being heard and granted; and between mental and aural prayer.

Looking at the Latin

Deus, exáudi oratiónem meam: áuribus pércipe verba oris mei.

O God, hear my prayer: give ear to the words of my mouth.

A word by word crib for the verse is:

Deus (God, voc), exáudi (hear, 2nd sg pres imperat act) oratiónem (prayer) meam (my): áuribus (with the ears) pércipe (hear/understand) verba (the words) oris (of the mouth) mei (of me).

exaudio, ivi, itum, ire, to hear, hearken to, listen to, give heed to; to regard, answer.

oratio, onis, f. prayer, supplication

auris, is, f the ear.

percipio, cepi, ceptum, ere 3 to perceive; to take wholly, seize entirely, take possession of, seize, occupy.

[Auribus percipe, hear, hearken, give ear to. ]

verbum, i, n.,word, command, edict, also a promise; saying, speech; Law, the Eternal Son.

os, oris, n., the mouth. 

Mental vs aural prayer

St Cassiodorus sees the verse as reflecting two types of prayer, that of our mind, and the audible prayers:

…because God could hear even a silent prayer, he added: Take in the words of my mouth, so that He should hear not merely the impulse of his heart but also the words of his mouth: The expression, take in, is notable, for the correct sense of take in is that we store things in the hidden depths of the mind.

St Augustine hinted at the same point when he said:

To You may my prayer attain, driven forth and darted out from the desire of Your eternal blessings: to Your ears I send it forth, aid it that it may reach, lest it fall short in the middle of the way, and fainting as it were it fall down. 

Listening vs answering

At the very least, the verse is a plea to grant the help asked for in the previous verse.  

St Robert Bellarmine, for example, commented:

Having acknowledged the power of the Lord, he now begs of him to apply his power to himself. “O God, hear my prayer;” I know you can do anything but I pray that you may wish to do it. I, therefore, ask that you may hear the prayer I put up to you, to exercise your power in saving me. He repeats it, “Give ear to the words of my mouth;” that is, turn not away your ears, and do not despise my prayer.

But St Thomas Aquinas introduced another nuance, pointing to a distinction between whether the prayer was heard and whether it was answered:

There are two things in his prayer, namely, that which is asked for, and the petition itself. When God hears the cause that is asked for, but not however, the petition itself, this is because that which is asked for is gotten by somebody out of grace and pity; and these are given by God. But the very same petition can be made by a sinner; and thus this is not heard, since it is not acceptable to God. So, he asks precisely that his prayer or petition be fulfilled when he says: O God, hear my prayer, and that his words be heard by [His] ears, Give ear to the words of my mouth, which takes place when God accepts and approves of his words; Psalm 5: Give ear, O Lord, to my words.

Why do we need to demand that God hear us?

Both St Hilary and St Augustine note that this psalm is intended to provide a model for us, encouraging us to keep on praying even when God seems to reject our petitions.  

St Augustine pointed to the example of St Paul, who three times had his prayer for freedom from temptations rejected, being told instead, ‘My Grace suffices for you’; St Hilary pointed to the model we are given in Christ in the Garden of Gethsemane.

The bottom line, according to St Augustine, is that we must seek to pray for the things that we need for our own good, and be open to God's prescriptions for us: 

… brethren, we admonish and exhort you in the Lord, that you ask not anything as if it were a thing settled, but that which God knows to be expedient for you. For what is expedient for you, you know not at all. Sometimes that which you think to be for you is against you, and that which you think to be against you is for you. For sick you are; do not dictate to the physician the medicines he may choose to set beside you.

Vulgate	Douay-Rheims
In finem, in carminibus. Intellectus David, 2 cum venissent Ziphæi, et dixissent ad Saul : Nonne David absconditus est apud nos?	Unto the end, in verses, understanding for David. 2 When the men of Ziph had come and said to Saul: Is not David hidden with us?
1 Deus, in nómine tuo salvum me fac: * et in virtúte tua júdica me.	3 Save me, O God, by your name, and judge me in your strength.
2  Deus, exáudi oratiónem meam: * áuribus pércipe verba oris mei.	4 O God, hear my prayer: give ear to the words of my mouth.
3  Quóniam aliéni insurrexérunt advérsum me, et fortes quæsiérunt ánimam meam: * et non proposuérunt Deum ante conspéctum suum.	5 For strangers have risen up against me; and the mighty have sought after my soul: and they have not set God before their eyes.
4 Ecce enim Deus ádjuvat me: * et Dóminus suscéptor est ánimæ meæ.	6 For behold God is my helper: and the Lord is the protector of my soul.
5  Avérte mala inimícis meis: * et in veritáte tua dispérde illos.	7 Turn back the evils upon my enemies; and cut them off in your truth.
6  Voluntárie sacrificábo tibi, * et confitébor nómini tuo, Dómine: quóniam bonum est :	8 I will freely sacrifice to you, and will give praise, O God, to your name: because it is good:
7  Quóniam ex omni tribulatióne eripuísti me: * et super inimícos meos despéxit óculus meus.	9 For you have delivered me out of all trouble: and my eye has looked down upon my enemies.

And for the next part in this series, continue on here.