According to Osho, grace is not occasional but the very nature of existence, like unceasing rain; we miss it only by erecting the ego's armor. When defense and doer-ship drop, through silence, love, and presence, we merge with the whole and grace floods in. It cannot be manufactured by effort; striving tightens the ego. Receptivity, not achievement, is the logic of grace.
Grace is always raining; you feel it when you put down the umbrella of your ego and simply be quiet and loving.