Avira> He called Rembrandt, .. a tzadik! Because he had one portrait of the tosfos yom tov
first, this is not the reason R Kook might have used, at least in the only source I found. Could you please elaborate?
Rembrand’s student van Hoogstraten painted Tosfos Yomtov and called him ‘Old Man in a Window.’
Rembrandt etched his neighbor Chacham Menashe B’ Israel – and seemingly did several illustrations to Menashe’s sefer. There are also interesting hidden parallels: Menashe brings only one of several ways how “mane tekel fares” might have looked on the wall – and that is how Rembrandt painted them a couple of years ago.