2 Timothy 1:8-12 – Therefore do not be ashamed of the testimony of our Lord or of me His prisoner, but join with me in suffering for the gospel according to the power of God,  who has saved us and called us with a holy calling, not according to our works, but according to His own purpose and grace which was granted us in Christ Jesus from all eternity,  but now has been revealed by the appearing of our Savior Christ Jesus, who abolished death and brought life and immortality to light through the gospel,  for which I was appointed a preacher and an apostle and a teacher.  For this reason I also suffer these things, but I am not ashamed; for I know whom I have believed and I am convinced that He is able to guard what I have entrusted to Him until that day.
There are some who teach a false doctrine of perfection for Christians. This doctrine teaches that it is possible for Christians to mature to the point that they no longer sin Romans 7:7-25 teaches us that if we attempt to keep the law through morality or legalism then we will experience that same frustration that Paul did about keeping the law. When we understand that it is not us who have overcome the world, but our Lord, then we will have a very different view of tribulation and peace in our Christian life.
Oswald Chambers wrote about this in the following devotional from My Utmost for His Highest.
I have said these things to you, that in me you may have peace. In the world you will have tribulation. But take heart; I have overcome the world.” (John 16:33 ESV)
As Christians we will always have troubles but God will be with us through them and will give us a way of escape.1 CORINTHIANS 10:13
KJ21 There hath no temptation taken hold of you but such as is common to man. But God is faithful; He will not suffer you to be tempted beyond that which ye are able to bear, but with the temptation will also make a way to escape, that ye may be able to bear it.
John 16:33 T
These things I have spoken unto you, that in me ye might have peace. In the world ye shall have tribulation: but be of good cheer; I have overcome the world.
In the world yet shall have tribulation: but be of good cheer, I have overcome the world, there is nothing for you to fear.
In John 16:33 our Lord tells us plainly that we should take heart even in the midst of tribulation if we are indeed in Him. A good parallel to this statement is found in 2 Timothy 1:12.
which is why I suffer as I do. But I am not ashamed, for I know whom I have believed, and I am convinced that he is able to guard until that Day what has been entrusted to me. (2 Timothy 1:12 ESV)
As Christians we should rejoice in our suffering because that is how we grow in our Christian life. We get stronger each time we go through a trial. We trust the Lord to get us through the hard times. We praise God as we go through our trials. We will come out as a better Christian and can serve God in a better way.