Kustić's columns (about one-fifth of the total number) were released in the form of a book in 2009, covering his writings in Glas Koncila over nearly forty years from the 1960s to the beginning of this century. Kustić dealt with various topics in addition to religion and theology, and he often delved into socio-political themes. Kustić's writing and editing in Glas Koncila under constant surveillance by the Commission for Relations with Religious Communities of the Socialist Republic of Croatia.

For example, the communist authorities had banned Glas Koncila no. 21 of 22 October 1972, in which they singled out among other things Kustić's article under the headline “Seventeen Centuries of Sacred Defiance.” In this article, Kustić took the example of St. Pollio, who preferred death because he did not want to forsake Christianity before the Roman prefect Probus. Kustić pointed out in this context the following: "St. Pollio claimed in particular that there are just laws that Christians are obliged to obey, but that the same authority could issues decrees that are not righteous, laws that a believer cannot accept" (Kustić 1972: 1). The communist authorities suggested, although he did not write it literally, that with these allusions Kustić had, in fact, "invited citizens to disobey and disrespect of the Constitution and laws of the Socialist Federal Republic of Yugoslavia and Socialist Republic of Croatia" (Mikić 2016: 445).