Objection 1. It would seem that the temptation of God is a graver sin than superstition. The greater sin receives the greater punishment. Now the sin of tempting God was more severely punished in the Jews than was the sin of idolatry; and yet the latter is the chief form of superstition: since for the sin of idolatry three thousand men of their number were slain, as related in Exodus 32:28 [Septuagint version]. The Vulgate has "twenty-three thousand."], whereas for the sin of temptation they all without exception perished in the desert, and entered not into the land of promise, according to Psalm 94:9, "Your fathers tempted Me," and further on, "so I swore in My wrath that they should not enter into My rest." Therefore to tempt God is a graver sin than superstition.
Objection 2. Further, the more a sin is opposed to virtue the graver it would seem to be. Now irreligion, of which the temptation of God is a species, is more opposed to the virtue of religion, than superstition which bears some likeness to religion. Therefore to tempt God is a graver sin than superstition.
Objection 3. Further, it seems to be a greater sin to behave disrespectfully to one's parents, than to pay others the respect we owe to our parents. Now God should be honored by us as the Father of all (Malachi 1:6). Therefore. temptation of God whereby we behave irreverently to God, seems to be a greater sin than idolatry, whereby we give to a creature the honor we owe to God.
On the contrary, A gloss on Deuteronomy 17:2, "When there shall be found among you," etc. says: "The Law detests error and idolatry above all: for it is a very great sin to give to a creature the honor that belongs to the Creator."
I answer that, Among sins opposed to religion, the more grievous is that which is the more opposed to the reverence due to God. Now it is less opposed to this reverence that one should doubt the divine excellence than that one should hold the contrary for certain. For just as a man is more of an unbeliever if he be confirmed in his error, than if he doubt the truth of faith, so, too, a man acts more against the reverence due to God, if by his deeds he professes an error contrary to the divine excellence, than if he expresses a doubt. Now the superstitious man professes an error, as shown above (94, 1, ad 1), whereas he who tempts God by words or deeds expresses a doubt of the divine excellence, as stated above (Article 2). Therefore the sin of superstition is graver than the sin of tempting God.
Reply to Objection 1. The sin of idolatry was not punished in the above manner, as though it were a sufficient punishment; because a more severe punishment was reserved in the future for that sin, for it is written (Exodus 32:34): "And I, in the day of revenge, will visit this sin also of theirs."
Reply to Objection 2. Superstition bears a likeness to religion, as regards the material act which it pays just as religion does. But, as regards the end, it is more contrary to religion than the temptation of God, since it implies greater irreverence for God, as stated.
Reply to Objection 3. It belongs essentially to the divine excellence that it is singular and incommunicable. Consequently to give divine reverence to another is the same as to do a thing opposed to the divine excellence. There is no comparison with the honor due to our parents, which can without sin be given to others.
Source: Summa Theologica (New Advent)