And it shall come to pass
John Calvin: That the people, then, might not form other expectations, God shows that all their hope was in him alone. He further shows that salvation was not to be sought afar off, provided the people had not forgotten the covenant, that God was dwelling in the midst of them.
Joel 2:28-32
“And it shall come to pass afterward,
that I will pour out my Spirit on all flesh;
your sons and your daughters shall prophesy,
your old men shall dream dreams,
and your young men shall see visions.
Even on the male and female servants
in those days I will pour out my Spirit.
“And I will show wonders in the heavens and on the earth, blood and fire and columns of smoke. The sun shall be turned to darkness, and the moon to blood, before the great and awesome day of the Lord comes. And it shall come to pass that everyone who calls on the name of the Lord shall be saved. For in Mount Zion and in Jerusalem there shall be those who escape, as the Lord has said, and among the survivors shall be those whom the Lord calls.”
