2 Thessalonians 3:3 But the Lord is faithful, who shall stablish you, and keep you from evil.
Faithfulness begins with a commitment to a task. God’s faithfulness is known and experienced in the careful, detailed fulfillment of His commitments. Just saying He is faithful is of little value without knowing what He purposed to do. And He has purposed to faithfully care for His children until they enter the eternal day and beyond.
In the previous chapter the Apostle Paul painted a bleak picture of the end times. It is a time filled with judgment and defection. But it is also a time for the Glory of God to be seen in His faithfulness. That is the way it always is with troubled times, and personal trouble in our own lives. Those are times for God’s faithfulness to be experienced by those who trust Him.
He is faithful. He is worthy of our faith because He will do everything He has promised to do. And in this case it is important to know that He will be with His children through the dark days. He will “stablish” them (put them on solid ground). He will "keep" them (to protect someone by taking careful measures and keeping them in close custody). Trust Him, He is worthy.