Isaiah 52:7-8 —
⁷     How beautiful on the mountains 
are the feet of those who bring good news, 
who proclaim peace, 
who bring good tidings, 
who proclaim salvation, 
who say to Zion , 
“Your God reigns!” 
⁸     Listen! Your watchmen lift up their voices; 
together they shout for joy. 
When the Lord returns to Zion , 
they will see it with their own eyes.

     An army could do nothing successfully if its different parts did not work in concert. Should each soldier act without reference to the others, the army would soon become disorganized. Instead of gathering strength from concentrated action, it would be wasted in desultory, meaningless efforts. Christ prayed that His disciples might be one with Him, as He was one with the Father. . . . 

     Whatever good qualities a man may have, he cannot be a good soldier if he acts independently. Good may occasionally be done but often the result is of little value, and often the end shows more mischief done than good. Those who act independently make a show of doing something, attract attention, and flash out brightly, and then are gone. All must pull in one direction in order to render efficient service to the cause. . . . 

     God requires concerted action of His soldiers, and in order to have this in the church, self-restraint is essential; self-restraint must be exercised.--Letter 11a, 1886. (3 Selected Messages – 24)
 

Acts 2:1 —
When the day of Pentecost came, they were all together in one place.

Those who belong to Christ’s army must work with concerted action. They cannot be faithful soldiers unless they obey orders. United action is essential. An army in which every part acts without reference to the other parts, has no real strength. In order to add new territory to Christ’s kingdom, His soldiers must act in concert. … He calls for a united army, which moves steadily forward, not for a company composed of independent atoms. The strength of His army is to be used for one great purpose. Its efforts are to be concentrated upon one great point—the magnifying of the laws of His kingdom before the world, before angels, and before men (MS 82, 1900). (Seventh-day Adventist Commentary 7A – 155)

Said the angel, "List ye!" Soon I heard a voice like many musical instruments all sounding in perfect strains, sweet and harmonious. It surpassed any music I had ever heard, seeming to be full of mercy, compassion, and elevating, holy joy. It thrilled through my whole being. Said the angel, "Look ye!" My attention was then turned to the company I had seen, who were mightily shaken. I was shown those whom I had before seen weeping and praying in agony of spirit. The company of guardian angels around them had been doubled, and they were clothed with an armor from their head to their feet. They moved in exact order, like a company of soldiers. Their countenances expressed the severe conflict which they had endured, the agonizing struggle they had passed through. Yet their features, marked with severe internal anguish, now shone with the light and glory of heaven. They had obtained the victory, and it called forth from them the deepest gratitude, and holy, sacred joy. (Christian Experience and Teachings – 176)