Blessed Theodoret writes that by depicting what is proper and belongs to God, the Apostle intended "to confirm the doctrine of the resurrection, judgment, and recompense." He wished to enliven and strengthen conviction in this for the same purpose, namely to quicken zeal. Nothing so strongly supports moral energy as remembrance of the last things.
God will show the appearing of the Lord, the Tri-hypostatic God. The incarnate Son will appear according to the will and good pleasure of the Father in communion with the Holy Spirit, as also happened at the first appearing for the ordering of salvation.
"In His own times" means at the time held in the mystery of the Godhead and known to Him alone. It means "at the fitting, proper time" (Saint Chrysostom), "the time foreordained" (Oecumenius, Blessed Theophylact). The Apostle said this to cut off the attempt, so characteristic of human weakness, to determine the moment of the Lord's appearing. Instead, he disposes us to expect Him at every minute.
The Lord will certainly appear and decide your lot forever. What need have you to know whether He will appear today or tomorrow? Be ready. That is what is needed.
After this are depicted the most impressive properties of the Godhead. The blessedness of God is placed first. God is blessed in Himself and worthy of being blessed by all the different creatures. That is, He is all-sufficient, all-perfect, the fullness of everything, and therefore worthy of all praise. "He is blessedness itself" (Saint Chrysostom).
If He is all-blessedness, then He desires nothing more than to bless all and to make all blessed. The appearing of the Lord is fearful, for it will be accompanied by the dread judgment. But it is also immeasurably joyful, for it will begin the all-blessed life, "where there will be neither sorrow nor sighing" (Saint Chrysostom).
Only be ready. "Do not look at the goods here that seem blessed, but fix your gaze on that One alone who is blessedness itself" (Blessed Theophylact), "from whose face every grief and sorrow flees" (Oecumenius). Then even here you will begin to taste the blessedness that will be fully revealed only after the appearing of the Lord.
"And only Sovereign," δυναστης, means the one Ruler. Everything is in His right hand. Consequently, He not only wills to bless all, but also has power to bless all. If we take into account everything recalled by the appearing of the Lord, then it means that He has power to raise all, gather them into one, conduct the judgment, divide them to the right and to the left, bless some and deliver others to eternal torments. He has power to seal all this unto ages of ages by His unchangeable decision and decree. For who can resist His will?
Among creatures also there are those who appear clothed with royal and lordly power, but they too are all in His authority. For He alone is King of kings and Lord of lords.
Therefore be fully confident that every promise of God will unfailingly be fulfilled. As no one compelled Him to make the promises, and they are the work of God's free good pleasure, so no one can hinder their fulfillment. God's decree concerning them will not change, for God is immutable.
Therefore be confident, but also fear. If everything is in His authority, then you have nowhere to flee or hide from Him if, by misfortune, you anger Him and deserve condemnation. Turn all your zeal to doing only what is pleasing before Him, and in the end to appearing acceptable to Him.
"Do not fear any earthly rulers and kings" (Blessed Theophylact), if they begin with threats to turn you away from what is pleasing to God.