Gad, a troop will press on him; but he will press on their heel. — Genesis 49:19
I can do all things through Christ, who strengthens me. — Philippians 4:13

Author
Charles Spurgeon
Summary: For a time, our adversaries may overcome us and celebrate a fleeting victory. Being attacked hurts, but we must not judge the war by its early setbacks: the promise sustains us with the assurance that we will prevail in the end. The Lord will grant final victory to truth and justice. Until that day, we need to persevere patiently in doing good and trust calmly in Christ, our Captain. He teaches us to stand firm as we complete our work or endure suffering, without giving up before we can say, “It is finished.”
Some of us have been like the tribe of Gad. For a time our adversaries were too numerous for us, and they came against us like a troop. Yes, and for a time they attacked us and showed great exultation over their temporary victory.
By this they only proved that the first part of our family inheritance is truly ours, for Christ’s people, like Dan, will be attacked by a troop. Being attacked is very painful, and we would have despaired if we had not believed by faith in the second part of our father’s blessing: “he shall attack at the last.” “All’s well that ends well,” said the poet of this world; and he spoke the truth. A war must be judged not by its first successes or setbacks, but by what happens “at the last.” The Lord will give victory to truth and righteousness “at the last”; and, as Mr. Bunyan says, that means forever, for nothing can come after the last.
What we need is patient perseverance in doing good, and quiet confidence in our glorious Captain. Christ, our Lord Jesus, wants to teach us His holy art of setting our faces like flint to complete our work or to endure our suffering until we can say, “It is finished.” Hallelujah. Victory! Victory! We believe the promise. “He shall attack at the last.”
Source: The Cheque Book of the Bank of Faith. Translation by Allan Roman.
http://www.spurgeon.com.mx/chequera/meditames/mayo.pdf