We are to approach G-d with reverence and awe, as well as to seek righteousness in the way we conduct our lives. That our lives should be imbued with holiness is a goal toward which all should aspire. Yet, we are not to raise ourselves above the definition of our calling. While, on the one hand, we speak of going from level to level, this is true and worthy to pursue in regard to our individual derech (path), comprising our journey of the soul, growing ever closer to HaSHem in service to Him. However, not all are called to be rabbis or congregational leaders in some capacity or another. Rather, we remain humbled in the eyes of G-d, when we are content with our positional bearings in a congregation and life at large.
Nadav and Avihu sought more than HaShem had bestowed upon them, in terms of their status and service toward G-d. They sought more than the fair portion that was allotted to them; and, they went beyond the boundary established for them. Was it status that they sought? Or a closer connection to G-d that they thought could be experienced by bringing an offering of their own design? Chazal teaches that they were both inclined toward a greater relationship with G-d than their station permitted, and were impatient with Moses and Aaron, seeking to usurp them, if only for a moment, when they perhaps thought their venture into the sanctuary would have gone unnoticed. Yet, G-d is omniscient, and a discerner of hearts.
The Torah records Moses recalling something that HaShem had told him earlier on, concerning those who are near to Him: “This is that HaShem spoke, saying: Through them that are nigh to Me I will be sanctified, and before all the people I will be glorified.” The Targum implies that the sanctity of the sanctuary was being protected, against the heedlessness of Nadav and Avihu, for they were not mindful of the true reverence toward G-d that is not a a selfish act, intended to benefit those who serve, rather that G-d is glorified in our service toward Him.
The Tree of Life 