For God hath not appointed us to wrath - This is designed as an encouragement to effort to secure our salvation. The wish of God is to save us, and therefore we should watch and be sober; we should take to ourselves the whole of the Christian armor, and strive for victory. If he had appointed us to wrath, effort would have been in vain, for we could do nothing but yield to our inevitable destiny. The hope of a final triumph should animate us in our efforts, and cheer us in our struggles with our foes. How much does the hope of victory animate the soldier in battle! When morally certain of success, how his arm is nerved! When everything conspires to favor him, and when he seems to feel that God fights for him, and intends to give him the victory, how his heart exults, and how strong is he in battle! Hence, it was a great point among the ancients, when about entering into battle, to secure evidence that the gods favored them, and meant to give them the victory.

For this purpose they offered sacrifices, and consulted the flight of birds and the entrails of animals; and for this armies were accompanied by soothsayers and priests, that they might interpret any signs which might occur that would be favorable, or to propitiate the favor of the gods by sacrifice. See Homer, passim; Arrian's Expedition of Alexander, and the classic writers generally. The apostle alludes to something of this kind here. He would excite us to maintain the Christian warfare manfully, by the assurance that God intends that we shall be triumphant. This we are to learn by no conjectures of soothsayers; by no observation of the flight of birds; by no sacrifice which we can make to propitiate his favor, but by the unerring assurance of his holy word. If we are Christians, we know that he intends our salvation, and that victory will be ours; if we are willing to become Christians, we know that the Almighty arm will be stretched out to aid us, and that the "gates of hell" cannot prevent it.

1 Thessalonians 5:9 Parallel Commentaries

Thirty-First Lesson. Pray Without Ceasing;'
Pray without ceasing;' Or, A Life of Prayer. Rejoice evermore. Pray without ceasing. In everything give thanks.--I Thess. v. 16, 17, 18. OUR Lord spake the parable of the widow and the unjust judge to teach us that men ought to pray always and not faint. As the widow persevered in seeking one definite thing, the parable appears to have reference to persevering prayer for some one blessing, when God delays or appears to refuse. The words in the Epistles, which speak of continuing instant in …
Andrew Murray—With Christ in the School of Prayer

Be Ye Therefore Perfect, Even as Your Father which is in Heaven is Perfect. Matthew 5:48.
In the 43rd verse, the Savior says, "Ye have heard that it hath been said, Thou shalt love thy neighbor, and hate thine enemy; but I say unto you, Love your enemies, bless them that curse you, do good to them that hate you, and pray for them which despitefully use you and persecute you, that ye may be the children of your Father which is in heaven: for he maketh his sun to rise on the evil and on the good, and sendeth rain on the just and on the unjust. For if ye love them which love you, what reward …
Charles G. Finney—Lectures to Professing Christians

Concerning Peaceableness
Blessed are the peacemakers. Matthew 5:9 This is the seventh step of the golden ladder which leads to blessedness. The name of peace is sweet, and the work of peace is a blessed work. Blessed are the peacemakers'. Observe the connection. The Scripture links these two together, pureness of heart and peaceableness of spirit. The wisdom from above is first pure, then peaceable' (James 3:17). Follow peace and holiness' (Hebrews 12:14). And here Christ joins them together pure in heart, and peacemakers', …
Thomas Watson—The Beatitudes: An Exposition of Matthew 5:1-12