A Prayer in Covenant Agreement

‘From whence come wars and fightings among you? come they not hence, even of your lusts that war in your members? Ye lust, and have not: ye kill, and desire to have, and cannot obtain: ye fight and war, yet ye have not, because you ask not. Ye ask, and receive not, because you ask amiss, that you may consume it upon your lusts. Ye adulterers and adulteresses, know ye not that the friendship of the world is enmity with God? whosoever therefore will be a friend of the world is the enemy of God. Do you think that the scripture saith in vain, "The spirit that dwelleth in us lusteth to envy?" But he giveth more grace. Wherefore he saith, "God resisteth the proud, but giveth grace to the humble." Submit yourselves therefore to God. Resist the devil, and he will flee from you. Draw nigh to God, and he will draw nigh to you. Cleanse your hands, ye sinners; and purify your hearts, ye double-minded. Be afflicted, and mourn, and weep: let your laughter be turned to mourning, and your joy to heaviness. Humble yourselves in the sight of the Lord, and he shall lift you up.' 

(James 4:1-10 KJV)

'Again I say unto you, That if two of you shall agree on earth as touching any thing that they shall ask, it shall be done for them of my Father which is in heaven. For where two or three are gathered together in my name, there am I in the midst of them.' (Matthew 18:19,20 KJV)

SHALL may be used to express simple futurity, determination; but in the archaic sense, used as CAN and even MUST. Let's insert those, in that way, into Jesus' instruction to His disciples:
'Again I say unto you, That if two of you (can) agree on earth as touching any thing that they (must) ask, it (can, must) be done for them of my Father which is in heaven.' Not to say that any may command anything of God, but that is His portion is the blood covenant of His Son!

In the name of Jesus Christ, we who can agree regarding what we must ask, shall receive of the Father the revelation of the testimony of the Son: humility over pride.