It means, {Indeed, Allah was pleased with the believers when they gave their pledge to you under the tree, He knew what was in their hearts, and He sent down tranquility upon them, and He rewarded them with a victory soon to come}
Aayadda 69 Suuratul Anfaal... (Ilaahay Mu'miniinta Raalli ayuu ka noqday markey geedka hoostiisa Ballanta kugula galeen, Qalbiyadooduuna Ogaadey Waxa Ku Jira, Naxariis iyo Xasiloonina waa kusoo dejiyey, Furasha Dhawna waa ugu abaal gudey iyo Qaniima Badan oo ay heli doonaan, Allaha Casiiskaa ee Xakiimkaa) Aayadda: 18 Suuratu Al Fatxi.