“Behold, I have refined thee, but not with silver; I have chosen thee in the furnace of affliction.”  Isaiah 48:10
Definition of affliction:  pain, suffering, distress. a state of pain, distress, or grief; misery: They sympathized with us in our affliction. A cause of mental or bodily pain, as sickness, loss, calamity, or persecution.  Synonyms:  mishap, trouble, tribulation, calamity, catastrophe, disaster. Affliction, adversity, misfortune, trial  refer to an event or circumstance that is hard to bear. A misfortune  is any adverse or unfavorable occurrence: He had the misfortune to break his leg. Affliction  suggests not only a serious misfortune but the emotional effect of this: Blindness is an affliction. Adversity  suggests a calamity or distress: Job remained patient despite all his adversities. Trial  emphasizes the testing of one’s character in undergoing misfortunes, trouble, etc.: His son’s conduct was a great trial to him.

Strongs defines affliction as “poor; humble; meek, Especially in later Israelite history, just before the Exile and following, this noun came to have a special connection with those faithful ones who were being abused, taken advantage of, by the rich ( Isaiah 29:19; Isa 32:7; Amos 2:7). The prophet Zephaniah’s reference to them as the “meek of the earth” (Zeph. 2:3) set the stage for Jesus’ concern and ministry to the “poor” and the “meek” (Matthew 5:3, 5; Luke 4:18; cf. Isaiah 61:1). By New Testament times, “the poor of the land” were more commonly known as “am ha’ares, “the people of the land.”   
Furnace:    an enclosed chamber in which heat is produced to generate steam, destroy refuse, smelt or refine ores, etc.
The heathen and lukewarm, pretend Christians also suffer times of tribulation and affliction; theirs is a preparation for the lake of fire for unbelievers or out of the kingdom realm after Bema Judgement for lukewarm Christians.* I’m not addressing them, I’m addressing “God’s People”, his true sheep, the ones who know The Great Shepherd of the Sheep “Jesus Christ” as their savior, and who hear His voice and follow, wherever that may lead.  These are the ones that are Chosen” (one who is the object of choice (the opportunity or right to choose between different things) by God, in other words God’s  Elect , also known as the Saints.  These are the ones that are chosen by God in the furnace of affliction and who spend a great deal of their lives in the furnace.  I’d rather say, from personal experience, “their entire life” is spent in the furnace of affliction.

Charles Spurgeon wrote a masterpiece on the subject of true Christians being chosen by God in the furnace of affliction. Please check it out: http://www.spurgeon.org/sermons/0035.htm
Here are a few quotes from the Charles Spurgeon link:
 “ we thank our enemies for all their shafts, for each one bears upon it proofs of our Father’s love.”

“God saith, “I have chosen thee in the furnace of affliction.” The fire is hot, but he has chosen me; the furnace burns, but he has chosen me; these coals are hot, the place I love not, but he has chosen me. Ah! it comes like a soft gale assuaging the fury of the flame. It is like some gentle wind fanning the cheeks; yea, this one thought arrays us in fireproof armour, against which the heat hath no power. Let affliction come—God has chosen me. Poverty, thou mayest come in at the door—God is in the house already, and he has chosen me. Sickness, thou mayest come, but I will have this by my side for a balsam—God has chosen me. Whatever it is, I know that he has chosen me.”

“The next comfort is that you have the Son of Man with you in the furnace. In that silent bedchamber of yours, there sitteth by your side one whom thou hast not seen, but whom thou lovest; and ofttimes when thou knowest it not, he makes all thy bed in thy affliction, and smoothes thy pillow for thee. Thou art in poverty; but in that lonely house of thine that hath nought to cover its bare walls, where thou sleepest on a miserable pallet, dost thou know that the Lord of life and glory is a frequent visitor; he often treads those bare floors, and putting his hands upon those walls he consecrates them! Wert thou in a palace he might not come there. He loves to come into these desolate places that he may visit thee. The Son of Man is with thee, Christian. Thou canst not see him, but thou mayest feel the pressure of his hands. Dost thou not hear his voice? It is the valley of the shadow of death: thou seest nothing; but he says, “Fear not, I am with thee; be not dismayed, for I am thy God.” It is like that noble speech of Caesar’s—”Fear not, thou carriest Caesar and all his fortune.” Fear not, Christian! thou carriest Jesus in the same boat with thee, and all his fortune! He is with thee in the same fire. The same fire that scorches thee, scorches him. That which could destroy thee could destroy him, for thou art a portion of the fulness of him that fills all in all. Wilt thou not take hold of Jesus, then, and say—
“Through floods and flames, if Jesus lead,
I’ll follow where he goes”   End quotes.
Be strong and encouraged during these last days dear saints.