What it is: Real presence
It is probably a very good exercise to practice “the imitation of Christ”, to walk “in his steps”, to ask “What would Jesus do?” in all circumstances. But the prayer we are teaching now is even better, for two reasons. First, invoking his name invokes his real presence, not mental imitation; something objective, not subjective; between us and him, not just in us. Second, it is actual, not potential; indicative, not subjunctive; “What is Jesus doing?” rather than “What would Jesus do?”
To invoke Jesus’ name is to place yourself in his presence, to open yourself to his power, his energy, The prayer of Jesus’ name actually brings God closer, makes him more present. He is always present in some way, since he knows and loves each one of us at every moment; but he is not present to those who do not pray as intimately as he is present to those who do. Prayer makes a difference; “prayer changes things.” It may or may not change our external circumstances. (It does if God sees that that change is good for us; it does not if God sees that it is not.) But it always changes our relationship to God, which is infinitely more important than external circumstances, however pressing they may seem, because it is eternal but they are temporary, and because it is our very self but they are not.