There is a somewhat surprising adjective used to refer to God in Psalm 75 (76). It is used thrice in the psalm, and it is "terrible". "Thou art terrible, and who shall resist thee?... Vow ye, and pay to the Lord your God: all you that are round about him bring presents. To him that is terrible, even to him who taketh away the spirit of princes: to the terrible with the kings of the earth".
God is terrible, then. Let's say He inspires terror and fear, He is so awesome that when one comes face to face with Him, one is overcome by trembling. That's the idea. It's important to keep in mind the context of the psalm in which a remembrance is made of the defeat of God's enemies: those who oppose Him have reason indeed to fear, for what appeared to be their might will be shattered to pieces by His omnipotence.
But all that is Old Testament theology, right? Wrong. It's so wrong that the Church of the New Testament thought it appropriate to use the verse in the sacred liturgy at, of all places, the communion verse on the 17th Sunday after Pentecost. It might seem out of place to put this verse on the lips of those who are about to approach the altar to receive the Bread of Angels. Or is it?
For many today, the Eucharist is essentially a holy meal at which we partake to be strengthened on our Christian path of life. But it is often forgotten that the One contained in the Holy Eucharist is the same God who is here, in this psalm, described as "terrible".
St Paul understood that when he wrote to the Corinthians (1 Co 11:27-29): "Whoever eats the bread or drinks the cup of the Lord unworthily will have to answer for the body and blood of the Lord. A person should examine himself, and so eat the bread and drink the cup. For anyone who eats and drinks without discerning the body, eats and drinks judgment on himself".
Such a teaching is based upon the reality that God is great, He is awesome. Before Him, the creature must humble himself, ever ready to receive God's grace, but conscious of the fact that it is not something he is entitled to.
And this is pre-eminently true when it comes to the Holy Eucharist, which contains the entire spiritual good of the Church. We must be immensely grateful for this ineffable Gift of God's presence, and strive to make ourselves less unworthy by confessing our sins before approaching the altar, firmly resolved to part with any evil-doing in our lives. Otherwise, the encounter with the all-loving God at Mass might end up being a worsening of our deeds, a provocation of the "terrible God".
On this feast of Corpus Christi then, let our love, devotion and and joy grow, but side by side with our respect, our adoration, our wholesome and God-saving fear of the Divine Majesty.