Presumptuous sins are normally committed by those who know better but willfully commit them anyway. The Hebrew word describing these sins, pesha' (Strong's #6588), is translated as "transgress," "transgressions," "transgressors," or "transgressed" many times.
The word contains a sense of expansion, of breaking away, or of continuousness, thus leading to its meaning "to revolt or rebel." It is translated as "transgressions" (plural) 48 times in the Old Testament, and interestingly, ten of those 48 occurrences—almost 20% of them—are in one book: Amos, which prophetically describes modern Israel.
Notice Amos 1:3: "Thus says the LORD: 'For three transgressions [pesha'] of Damascus, and for four, I will not turn away its punishment, because they have threshed Gilead with implements of iron.'" It may be surprising to realize that God makes this charge against a Gentile nation—those who are supposedly without the law and therefore somewhat excusable. Yet He charges them with "transgressions"—rebellion. In other words, on some level, they really did know better.
God's charge indicates a sin so bold, so vicious, so in-your-face, and so continuous in its revolting attitude that it cannot be passed over on the basis of ignorance or inadvertence. Of special note in this level of sin is its continuous nature. In other words, the sinner is not really fighting it. I Kings 12:19 says, "So Israel has been in rebellion against the house of David to this day." "In rebellion" is translated from pâsha', the root of pesha'.
Amos 2:4-6 carries God's charge against both Israel and Judah:
Thus says the LORD: "For three transgressions [pesha'] of Judah, and for four, I will not turn away its punishment, because they have despised the law of the LORD, and have not kept His commandments. Their lies lead them astray, lies after which their fathers walked. But I will send a fire upon Judah, and it shall devour the palaces of Jerusalem." Thus says the LORD: "For three transgressions [pesha'] of Israel, and for four, I will not turn away its punishment, because they sell the righteous for silver, and the poor for a pair of sandals."
In contrast to the Gentiles, it is not so much the vicious intensity of Judah's and Israel's sins, but their continuous, revolting, grasping nature that so incenses God. In other words, the Israelitish people give every impression from their long history that they made little or no effort to stop sinning. Israel's problem is not so much an in-your-face willfulness, but a persistent, casual, hardheaded, self-centered, "I'll take care of it later" attitude.