National Sunday Law Info

EGW says when the Sunday Law is passed either you receive the latter rain outpouring or you do not, and if you do not you are lost. So at the Sunday Law, God needs to already know if He can pour out the latter rain on you or not, therefore you have to be sealed by the Sunday Law. That is why EGW says it is the great test to the people of God:  
If the believers in the truth are not sustained by their faith in these comparatively peaceful days, what will uphold them when the grand test comes and the decree goes forth against all those who will not worship the image of the beast and receive his mark in their foreheads or in their hands? —Testimonies for the Church 4:251 (1876). {LDE 223.3}
Here are another few quotes proving the same:
What are you doing, brethren, in the great work of preparation? Those who are uniting with the world, are receiving the worldly mold, and preparing for the mark of the beast. Those who are distrustful of self, who are humbling themselves before God and purifying their souls by obeying the truth,—these are receiving the heavenly mold, and preparing for the seal of God in their foreheads. When the decree goes forth, and the stamp is impressed, their character will remain pure and spotless for eternity{CET 191.1}