Our word majesty comes from the Latin; it means greatness. When we ascribe majesty to someone, we are acknowledging greatness in that person....Now majesty is a word the bible uses to express the thought of the greatness of God..."The Lord reigns, he is robed in majesty" (Ps 93:1-2). "They will speak of the glorious splendor of your majesty" (Ps 145:5). Peter recalling his vision of Christ's royal glory at the transfiguration, says, "We were eyewitnesses of his majesty" (2 Pet 1:16).
The word majesty, when applied to God, is always a declaration of his greatness and an invitation to worship....The Christian's instincts of trust and worship are stimulated very powerfully by knowledge of the greatness of God.
But this is knowledge which Christians today largely lack; and that is one reason why our faith is so feeble and our worship so flabby. We are modern people and modern people, though they cherish great thoughts of themselves, have as a rule small thoughts of God. When the person in the Church let alone the person in the street uses the word God, the thought is rarely of divine majesty.
J.I. Packer, Knowing God, pg. 82-83