9th Ordinary Sunday (Year A)

Fr. Patrick Sun brought up a very powerful image to illustrate the Gospel teaching today Matthew 7:21-27. In the wake of Sichuan earthquake, many schools collapsed and killed almost all the school children inside. These 'tofu' structures illustrated vividly the price a country needs to pay to feed corrupt officials. However, some schools are able to withstand the quake and none of the school children, nor teachers are injured or die. In particular, one principal found his 170,000 RMB school unsafe. He took nearly a decade to raise fund and rebuild the school, totally 400,000 RMB. In this quake, his school is one of those remain standing, with zero casualty.
"Not every one who says to me, `Lord, Lord,' shall enter the kingdom of heaven, but he who does the will of my Father who is in heaven (Matthew 7:21).
"Every one then who hears these words of mine and does them will be like a wise man who built his house upon the rock;
and the rain fell, and the floods came, and the winds blew and beat upon that house, but it did not fall, because it had been founded on the rock (Matthew 7:24-25).
Today, we also read of Romans 3. The little exercise yesterday shows that Paul translated Deuteronomy himself. But immediately, he copies from the Septuagint Proverbs. Paul was a Pharisee. He must be competent enough in Pentateuch. He was an expert in law, but might not be one in literature. As for the Holy Writings, among which can be found Proverbs, Psalms etc., Paul might have a working knowledge of them but not as strong as in Pentateuch.  So, he preferred to copy from the Septuagint. This is only a hypothesis. I wonder if Romans 3:10-18 would yield more lights on the matter.
Romans 3:10-18 is a long string of OT quotations from various sources. I will list and highlight them one by one.
as it is written: "None is righteous, no, not one;
καθὼς γέγραπται ὅτιοὐκ ἔστιν δίκαιος οὐδὲ εἷς, (Romans 3:10)
ὅτι ἄνθρωπος οὐκ ἔστιν δίκαιος ἐν τῇ γῇ, ὃς ποιήσει ἀγαθὸν καὶ οὐχ ἁμαρτήσεται. (Ecclesiastes 7:20)
no one understands, no one seeks for God
All have turned aside, together they have gone wrong; no one does good, not even one." 
οὐκ ἔστιν ὁ συνίων,οὐκ ἔστιν ὁ ἐκζητῶν τὸν θεόν.
πάντες ἐξέκλιναν ἅμα ἠχρεώθησαν· οὐκ ἔστιν ὁ ποιῶν χρηστότητα,[οὐκ ἔστιν] ἕως ἑνός. (Romans 3:11-12).
κύριος ἐκ τοῦ οὐρανοῦ διέκυψεν ἐπὶ τοὺς υἱοὺς τῶν ἀνθρώπων τοῦ ἰδεῖν εἰ ἔστιν συνίων ἢ ἐκζητῶν τὸν θεόν.
πάντες ἐξέκλιναν, ἅμα ἠχρεώθησαν, οὐκ ἔστιν ποιῶν χρηστότητα, οὐκ ἔστιν ἕως ἑνός. (Psalm 13:2-3 LXX, Psalm 14:2-3 BHS)
The Lord from out of heaven looked upon the sons of man to see if there is anyone perceiving and inquiring after God (Brenden)
"Their throat is an open grave, they use their tongues to deceive."
τάφος ἀνεῳγμένος ὁ λάρυγξ αὐτῶν,ταῖς γλώσσαις αὐτῶν ἐδολιοῦσαν, (Romans 3:13a)
ὅτι οὐκ ἔστιν ἐν τῷ στόματι αὐτῶν ἀλήθεια, ἡ καρδία αὐτῶν ματαία, τάφος ἀνεῳγμένος ὁ λάρυγξ αὐτῶν, ταῖς γλώσσαις αὐτῶν ἐδολιοῦσαν. (Psalm 5:10)
"The venom of asps is under their lips."
ἰὸς ἀσπίδων ὑπὸ τὰ χείλη αὐτῶν (Romans 3:13b)
ἠκόνησαν γλῶσσαν αὐτῶν ὡσεὶ ὄφεως, ἰὸς ἀσπίδων ὑπὸ τὰ χείλη αὐτῶν. διάψαλμα. (Psalm 139:4 LXX, Psalm 140:4 BHS)
"Their mouth is full of curses and bitterness."
ὧν τὸ στόμα ἀρᾶς καὶ πικρίας γέμει, (Romans 3:14)
οὗ ἀρᾶς τὸ στόμα αὐτοῦ γέμει καὶ πικρίας καὶ δόλου, ὑπὸ τὴν γλῶσσαν αὐτοῦ κόπος καὶ πόνος. (Psalm 9:28 LXX, Psalm 10:7 BHS)
"Their feet are swift to shed blood,
in their paths are ruin and misery,
and the way of peace they do not know."
ὀξεῖς οἱ πόδες αὐτῶν ἐκχέαι αἷμα,
σύντριμμα καὶ ταλαιπωρία ἐν ταῖς ὁδοῖς αὐτῶν,
καὶ ὁδὸν εἰρήνης οὐκ ἔγνωσαν. (Romans 3:15-17)
οἱ δὲ πόδες αὐτῶν ἐπὶ πονηρίαν τρέχουσιν ταχινοὶ ἐκχέαι αἷμα, καὶ οἱ διαλογισμοὶ αὐτῶν διαλογισμοὶ ἀφρόνων, σύντριμμα καὶ ταλαιπωρία ἐν ταῖς ὁδοῖς αὐτῶν. 
καὶ ὁδὸν εἰρήνης οὐκ οἴδασιν, καὶ οὐκ ἔστιν κρίσις ἐν ταῖς ὁδοῖς αὐτῶν, αἱ γὰρ τρίβοι αὐτῶν διεστραμμέναι, ἃς διοδεύουσιν, καὶ οὐκ οἴδασιν εἰρήνην. (Isaiah 59:7-8)
Both words in red means "to know".
"There is no fear of God before their eyes."
οὐκ ἔστιν φόβος θεοῦ ἀπέναντι τῶν ὀφθαλμῶν αὐτῶν. (Romans 3:18)
Φησὶν ὁ παράνομος τοῦ ἁμαρτάνειν ἐν ἑαυτῷ, οὐκ ἔστιν φόβος θεοῦ ἀπέναντι τῶν ὀφθαλμῶν αὐτοῦ, (Psalm 35:2 LXX, Psalm 36:2 BHS)
Paul, the Pharisee, knew the Pentateuch well enough to translate it into Greek by himself. In the Wisdom Writings, he relied on Septuagint and copied from it. The case of the Prophet Isaiah needs further analysis. All this can only be a conjecture.

My Advocate, I thank You for the interest You arouse in me. May I benefit and be nourished by Your revelation and learn from the saints of the earlier generations. Amen.