Our heavenly calling is not in itself our union with Christ at all. It is very important to make the difference. Those who have the heavenly calling may be united. But union with Christ is not a calling but a state, an acquired place and position. A calling is that to which we are called by faith and is never in itself union, though those called may be united. My calling is that which God has set before my soul, as that which is to form my soul, by my heart being set upon it as given to me by grace, and by grace called to it, and Scripture constantly deals with the soul on this ground.
J. N. Darby from Collected Writings, Vol. 15