Being comforted

Psalm 119: 153. — Consider mine affliction. These prayers of David are penned with such heavenly wisdom that they are convenient for the state of the whole church, and every member thereof. The church is the bush that burns with fire, but cannot be consumed; every member thereof bears a part of the cross of Christ; they are never without some affliction, for which they have need to pray with David, "Behold mine affliction."

We know that in afflictions it is some comfort to us to have our crosses known to those of whom we are assured that they love us: it mitigates our dolour when they mourn with us, albeit they be not able to help us. But the Christian has a more solid comfort; to wit, that in all his troubles the Lord beholds him; like a king, rejoicing to see his own servant wrestle with the enemy. He looks on with a merciful eye, pitying the infirmity of his own, when he sees it; and with a powerful hand ready to help them. But because many a time the cloud of our corruption comes between the Lord and us, and lets us not see his helping hand, nor his loving face looking upon us, we have need to pray at such times with David, "Behold mine affliction." — William Cowper.

From the additional notes to Charles Spurgeon's The Treasury of David. 

1 Corinthians 4 seems apt to this:

Who comforteth us in all our tribulation, that we may be able to comfort them which are in any trouble, by the comfort wherewith we ourselves are comforted of God. [I love the way this line seems to revolve in on itself...]

Satan's lies

From the additional notes to Charles Spurgeon's The Treasury of David, on Psalm 119, verse 86. 

All thy commandments are faithful. David sets down here three points. The one is that God is true; and after that he adds a protestation of his good conduct and guidance, and of the malice of his adversaries: thirdly, he calls upon God in his afflictions. Now as concerning the first, he shows us that although Satan [intends] to shake us, and in the end utterly to carry us away, subtly and cunningly goes about to deceive us, we must, to the contrary, learn how to know his ambushes, and to keep us from out of them. So often then as we are grieved with adversity and affliction, where must we begin? See Satan how he pitches his nets and lays his ambushes to induce and persuade us to come into them, what saith he? Dost thou not see thyself forsaken of thy God? Where are the promises whereunto thou didst trust? Now here thou sees thyself to be a wretched, forlorn creature. So then thou right well sees that God hath deceived thee, and that the promises whereunto thou trusts appertain nothing at all unto thee. See here the subtlety of Satan. What is now to be done? We are to conclude with David and say, yet God is true and faithful. Let us, I say, keep in mind the truth of God as a shield to beat back whatsoever Satan is able to lay unto our charge. When he shall go about to cause us to deny our faith, when he shall lie about us to make us believe that God thinks no more of us, or else that it is in vain for us to trust unto his promises; let us know the clean contrary and believe that it is very plain and sound truth which God saith unto us. Although Satan casts at us never so many darts, although he have never so exceeding many devices against us, although now and then by violence, sometimes with subtlety and cunning, it seems in very deed to us that he should overcome us; nevertheless he shall never bring it to pass, for the truth of God shall be made sure and certain in our hearts. — John Calvin.

The limit of afflictions

From the additional notes to Charles Spurgeon's The Treasury of David, on Psalm 119:84

Verse 84. — How many are the days of thy servant? When will thou execute judgement on them that persecute me?

Some read the two clauses apart, as if the first were a general complaint of the brevity of human life, such as is to be met with in other Psalms, and more frequently in the book of Job; and next, in their opinion, there follows a special prayer of the Psalmist that God would take vengeance upon his enemies. But I rather prefer joining the two clauses together, and limit both to David's afflictions; as if it had been said, Lord, how long hast thou determined to abandon thy servant to the will of the ungodly? when wilt thou set thyself in opposition to their cruelty and outrage, in order to take vengeance upon them? The Scriptures often use the word "days" in this sense... By the use of the plural number is denoted a determinate portion of time, which, in other places, is compared to the "days of an hireling": Job 14:6; Isaiah 16:14. The Psalmist does not, then, bewail in general the transitory life of man, but he complains that the time of his state of warfare in this world had been too long protracted; and, therefore, he naturally desires that it might be brought to a termination. In expostulating with God about his troubles, he does not do so obstinately, or with a murmuring spirit; but still, in asking how long it will be necessary for him to suffer, he humbly prays that God would not delay to succour him. — John Calvin.
 

Affliction

From the additional notes to Charles Spurgeon's The Treasury of David, on Psalm 119 verse 71. 

It is good for me to be afflicted. I am mended by my sickness, enriched by my poverty, and strengthened by my weakness, and with Saint Bernard desire, "Irasecaris mihi; Domine", O Lord, be angry with me. For if you chide me not, you consider me not; if I taste no bitterness, I have no physic; if you correct me not, I am not thy son. Thus was it with the great grandchild of David, Manasseh, when he was in affliction, "He besought the Lord his God": even that king's iron was more precious to him than his gold, his jail a more happy lodging than his palace, Babylon a better school than Jerusalem. What fools are we, then to frown upon our afflictions! These, how crabbed soever, are our best friends. They are not indeed for our pleasure, they are for our profit; their issue makes them worthy of a welcome. What do we care how bitter that potion be that brings Health. — Abraham Wright [most likely from A Practical Commentary on the Psalms,’ 1661]

  
It's worth adding another comment, this time from George Bowen [in his Daily Meditations]:
Even the profoundest affliction does not, perhaps, teach us everything; a mistake we sometimes make. But why should we compel God to use harsh measures with us? Why not sit at the feet of Jesus and learn quietly what we need to learn?