I believe there are two components to be understood when going through the fiery trial of faith. There is the attempt of the enemy to create an offense toward God and there is the redemptive work of faith during the trial that serves God's purposes.
I have noticed one does not have to pray that trials would come to strengthen our faith, they just keep showing up. In every trying situation God has promised that what the enemy has meant for evil, God will make it work for good ― not only for the one going through it, but for those who ultimately receive the benefit of our trial.
Not everything that happens to us is sent by God, but everything will bow to the supremacy of God's will and purposes regardless of the enemies attempt to damage or destroy our lives and our faith in the goodness of God.
The first thing I believe Satan wants to do to us when a severe trial comes is to create an offense toward God. Satan is not only the accuser of the brethren, but he delights to raise questions about the goodness and character of God. All too often we ask the question, "why" God, rather than asking "what" is the purpose of the test.
God never gives a test that He wants us to fail ... it is always to discover the majesty, supremacy and goodness of the Father's heart toward us. It is not easy to understand with our human reasoning; that is why in the book of James chapter one verses 2-8 he encourages us to "ask of God for wisdom" when the trial comes.
It's not the "why" it is the "what" that wisdom cries for, and God does not deride us but gives liberally without reproach. We must remember no weapon formed against us will prosper, but that does not preclude a weapon will not be formed; it just will not prosper.
Satan's job description is clear: "the thief comes to steal, kill and destroy." (John 10:10) What he cannot steal, he will try to kill, what he cannot kill, he will try to destroy so that it is useless for anyone or anything. Jesus said "I have come to give you life and that more abundantly."
Genesis 50:20 tells the story of Joseph's brothers seeking forgiveness for the cruel plot that put him in Egypt. They were astonished by the perspective Joseph had that removed the fear of retribution and released forgiveness to them. Too often believers look for an immediate purpose or reason for the trial and like Josephs experience, the timing of the Lord will show how God turns the end result to our good and His glory.
The second thing I see is that the enemy would seek to injure our intimacy and trust in Jesus. Remember the disciples in the stormy sea, thinking they would soon capsize, cried out to Jesus sleeping in the bow of the boat, "don't you care we are perishing"? If we have questions it’s time for an intimate conversation with the lover of our soul, not an accusation that He does not care about the storm that threatens.
When you know the Lord intimately you come to know and trust that He has only good plans for your life. The enemy is always ready to plant a seed of doubt through the voices that shout out "There's no hope for him in God." (Psalm 3:2) Our great weapon of spiritual warfare is to meditate day and night on the great and precious promises given to us and the power of praise.
The word of God will "cast down" or dislodge every argument and every high thing that exalts itself against the knowledge of God." The strongholds of carnal thinking must be violently "cast down" and that is accomplished by praise and worship to the most high God. Psalm 149:5-9 states "let the high praises of God be in our mouths, and the two-edged sword of the word in our hand … to bind spiritual principalities and powers of darkness with chains and demonic nobles with fetters of iron."
Remember the trial of your faith being much more precious than gold that perishes. Though it be tried with fire, may your faith be found to bring praise and honor and glory to the Lord Jesus when He returns for the church, His bride.