7 “I will hearken”. The Prophet spoke: God spoke within in him, and the world made a noise without. Therefore, retiring for a little from the noise of the world, and turning himself back upon himself, and from himself upon Him whose voice he heard within; sealing up his ears, as it were, against the tumultuous disquietude of this life, and against the soul weighed down by the corruptible body, and against the imagination, that through the earthly tabernacle pressing down, thinks on many things, he says, “I will hearken what the Lord God speaks in me;” and he heard, what?
“For He shall speak peace unto His people.” The voice of Christ, then, the voice of God, is peace: it calls unto peace. Ho! It says, whosoever are not yet in peace, love ye peace: for what can you find better from Me than peace? What is peace? Where there is no war. What is this, where there is no war? Where there is no contradiction, where there is no resistance, nothing to oppose. Consider if we are yet there: consider if there is not now a conflict with the devil, if all the saints and faithful ones wrestle not with the prince of demons.
And how do they wrestle with him whom they see not? They wrestle with their own desires, by which he suggests unto them sins: and by not consenting to what he suggests, though they are not conquered, yet they fight. Therefore there is not yet peace where there is fighting....Whatever we provide for our refreshment, there again we find weariness. Are you hungry? One asks you: you answer I am. He places food before you for your refreshment; continue thou to use it, for you had need of it; yet in continuing that which you need for refreshment, therein do you find weariness.
By long sitting you were tired; you rise and refreshest yourself by walking; continue that relief, and by much walking you are wearied; again you would sit down. Find me anything by which you are refreshed, wherein if you continue thou dost not again become weary. What peace then is that which men have here, opposed by so many troubles, desires, wants, wearinesses? This is no true, no perfect peace. What will be perfect peace? “This corruptible must put on incorruption, and this mortal must put on immortality.”...Persevere in eating much; this itself will kill you: persevere in fasting much, by this you will die: sit continually, being resolved not to rise up, by this you will die: be always walking so as never to take rest, by this you will die; watch continually, taking no sleep, by this you will die; sleep continually, never watching, thus too you will die.
When therefore death shall be swallowed up in victory, these things shall no longer be: there will be full and eternal peace. We shall be in a City, of which, brethren, when I speak I find it hard to leave off, especially when offenses wax common. Who would not long for that City whence no friend goes out, whither no enemy enters, where is no tempter, no seditious person, no one dividing God's people, no one wearying the Church in the service of the devil; since the prince himself of all such is cast into eternal fire, and with him those who consent unto him, and who have no will to retire from him?
There shall be peace made pure in the sons of God, all loving one another, seeing one another full of God, since God shall be all in all. We shall have God as our common object of vision, God as our common possession, God as our common peace. For whatever there is which He now gives unto us, He Himself shall be unto us instead of His gifts; this will be full and perfect peace. This He speaks unto His people: this it was which he would hearken unto who said, “I will hearken what the Lord God will say unto me: for He shall speak peace unto His people, and to His saints, and unto those who turn their hearts unto Him.”
Lo, my brethren, do ye wish that unto you should belong that peace which God utters? Turn your heart unto Him: not unto me, or unto that one, or unto any man. For whatever man would turn unto himself the hearts of men, he falls with them. Which is better, that you fall with him unto whom you turn yourself, or that thou stand with Him with whom you turn yourself? Our joy, our peace, our rest, the end of all troubles, is none but God: blessed are “they that turn their hearts unto Him.”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)