Lord Allah didn’t make it except as glad news and tranquil to your hearts with it; there is no help except Allah; indeed, Allah is the Exalted, the Wise.
Everything happening in the universe is with the decree and knowledge of Three-Time-Knower Lord as explained in verse 6: 59. The Wise Exalted Lord doesn’t want to send the Angels for helping the believers; because if He intends a thing, He says: “Be”, then it is.
The believer is the vicegerent of Lord, and so with the Remembrance of Lord with Adhikr, he will not be affected by any distress from Satan’s part as explained in verses 2: 152 and 3: 190-191. It is told in verses 36: 28-29: “And We didn’t send down upon his people any soldier from heaven after him, nor would We have done so. It was nothing but one shout, and immediately they were extinguished”. Therefore, the believer has the confidence that for helping them, Allah doesn’t want to send any troops or Angels. Believer is the one who keeps Lord in his heart with Adhikr—the Safeguard---as explained in verses 3: 101-103.
Since today, as there is no group of believers anywhere in the world, there is no war. Instead, the odd-believer must do great Jihad against the Kuffar and hypocrites with Adhikr—the Strong Weapon—as explained in verse 9: 73. See explanation3: 79, 125-127; 8: 2-4 and 9: 32-33.