“For the eyes of the Lord are upon the righteous, and his ears are open to their prayer...” (1 Peter 3:12)
James 5:16-18 (RSV) “. . . The prayer of a righteous man has great power in its effects. Eli’jah was a man of like nature with ourselves and he prayed fervently that it might not rain, and for three years and six months it did not rain on the earth. Then he prayed again and the heaven gave rain, . . . (cf. 1 Kgs 17:1)
Protestants often assert that all prayers are exactly the same under God: that whoever prays has the same impact as anyone else, regardless of the level of holiness and righteousness in the person.
Protestants don’t care for any notion of merit achieved (by God’s grace, but with our “synergistic” cooperation) on the part of the believer: we’re all equally fallen, utterly wicked sinners, etc. This is especially true in the case of Calvinism.
But God’s inspired revelation repeatedly states that prayers of holy people are far more powerful and that God is more inclined to answer them. Once this is grasped, and once it is understood that saints who are in heaven are aware of us and can and do pray and intercede for us, then the Catholic rationale for asking saints (above all, the Blessed Virgin Mary) to intercede is abundantly established as an eminently biblical practice.
Many Protestants, however, almost despite their theology, do indeed recognize that this is the case: at least insofar as other people now living on the earth are concerned, since they will ask pastors to pray for them, thinking that this will help them more than asking the next person in the pew to do so.
I always use the example of a Protestant asking the late great Billy Graham to pray for them. This is so because Billy Graham was respected as a man of God and was considered to be a person who was closer to God; therefore his prayers have more effect. That is exactly correct . . . Thus, as so often, in practice, Protestants confirm a truth that is emphasized in the Catholic faith. Scripture confirms this teaching again and again:
Genesis 18:26-28, 32 And the LORD said, “If I find at Sodom fifty righteous in the city, I will spare the whole place for their sake.”  Abraham answered, “Behold, I have taken upon myself to speak to the Lord, I who am but dust and ashes.  Suppose five of the fifty righteous are lacking? Wilt thou destroy the whole city for lack of five?” And he said, “I will not destroy it if I find forty-five there.” . . .  Then he said, “Oh let not the Lord be angry, and I will speak again but this once. Suppose ten are found there.” He answered, “For the sake of ten I will not destroy it.”
Genesis 20:7 Now then restore the man’s wife; for he is a prophet, and he will pray for you, and you shall live. . . .
Numbers 11:2 Then the people cried to Moses; and Moses prayed to the LORD, and the fire abated.
Numbers 14:19-20 Pardon the iniquity of this people, I [Moses] pray thee, according to the greatness of thy steadfast love, and according as thou hast forgiven this people, from Egypt even until now.”  Then the LORD said, “I have pardoned, according to your word;
Numbers 21:7-8 And the people came to Moses, and said, “We have sinned, for we have spoken against the LORD and against you; pray to the LORD, that he take away the serpents from us.” So Moses prayed for the people.  And the LORD said to Moses, “Make a fiery serpent, and set it on a pole; and every one who is bitten, when he sees it, shall live.”
Deuteronomy 10:10 . . . the LORD hearkened to me [Moses] that time also; the LORD was unwilling to destroy you. (cf. 9:18-20)
1 Samuel 12:18 So Samuel called upon the LORD, and the LORD sent thunder and rain that day; . . . (cf. 7:8; 1 Kgs 13:6)
1 Kings 17:22 And the LORD hearkened to the voice of Eli’jah; and the soul of the child came into him again, and he revived. (cf. 2 Kgs 1:10)
2 Kings 4:32-34 When Eli’sha came into the house, he saw the child lying dead on his bed.  So he went in and shut the door upon the two of them, and prayed to the LORD.  Then he went up and lay upon the child, putting his mouth upon his mouth, his eyes upon his eyes, and his hands upon his hands; and as he stretched himself upon him, the flesh of the child became warm. (cf. Acts 9:36-40 [Peter], 20:9-10 [Paul], Mt 10:8)
2 Kings 6:18 And when the Syrians came down against him, Eli’sha prayed to the LORD, and said, “Strike this people, I pray thee, with blindness.” So he struck them with blindness in accordance with the prayer of Eli’sha. (cf. 6:17)
2 Chronicles 30:20 And the LORD heard Hezeki’ah, and healed the people.
Job 42:8 . . . my servant Job shall pray for you, for I will accept his prayer . . .
Proverbs 15:29 The LORD is far from the wicked, but he hears the prayer of the righteous. (cf. 15:8)
Sirach 35:16 He whose service is pleasing to the Lord will be accepted, and his prayer will reach to the clouds. Cf. Sir. 28:2)
John 15:7 If you abide in me, and my words abide in you, ask whatever you will, and it shall be done for you.
James 4:3 You ask and do not receive, because you ask wrongly, to spend it on your passions.
1 Peter 3:12 For the eyes of the Lord are upon the righteous, and his ears are open to their prayer. . . .
1 John 3:22 and we receive from him whatever we ask, because we keep his commandments and do what pleases him.