According to the Rambam (this is not the only interpretation) Makkos 3,16 The Passuk could be referring to doing all of one Mitzva the result of which one will attain Olam Haba (see Rashi who says on the passuk is referring to attainment of world to come"היום לעשותם" - ולמחר לעולם הבא ליטול שכרם):
רבי חנניא בן עקשיא אומר רצה הקב"ה לזכות את ישראל לפיכך ...
What did Moshe mean in Devarim 7:7 by we (Jews) are few in number?
For a short answer: Yes. We were fewest among the nations. But Abraham’s descendants will be as numerous as the stars.
I am convinced that the Bible always, not just sometimes, exaggerates numbers to make an impact. I think the total number of Israelites that left Egypt with some Egyptian ...
The commentator Rashi explains that the reference is not to numbers, but to estimation:
you regard yourselves as small, as, e.g., Abraham did who said, (Genesis 18:27) “For I am dust and ashes", and as, e.g., Moses and Aaron did who said, (Exodus 16:7) “And we, what are we?".
Rashi to Tehillim 36:3 seems to write the way you understand it (ie Hashem causes the rasha to slip/err):
כי החליק. הפשע על הרשע בחלקלקות בעיניו כדי שימצא הקב"ה את עונו לשנוא אותו:
Hashem has the wicked one sin through the smoothing over the transgression in [the rasha's] eyes in order that Hashem finds his sin to hate
Edit: after reading Tehillim 36:2 on Tehilim, It should be read like this:
He (The sin, Yetzer Hara) made him (the evil man)think that he is "covered/smooth", [but that's just] in his (the evil man) eyes, [to make god] find his sin, and hate him (the evil man).
it could be read:
He (הרשע) caused him[self] to smooth/cover [his own evil deeds]...