The paper is aimed at reviewing and analyzing the main concepts and phenomena that could be counted as generative factors for the sustainable financial source. In this context, the economic process, the economic resources and the economic environment are analyzed under the aspect of their predicates concerning the sustainability. Some appeals are made to the entropic model of the economic process, to get the main predicates of the sustainability of the financial source. The authors establish the "decalogue" of the sustainable financial source as the sum of the six first order necessary predicates (the same with the six sufficient predicates) and the four second order necessary predicates (that are generated by the six predicates). All results are obtained in a qualitative way as well as in a logical form. The final results propose a list of the sufficient and necessary conditions for any abstract sustainable financial resource. These conditions are also discussed from the point of view of the feeds-back and feeds-before that could affect the sustainability of the financial source. Some conceptual proposals and methodological hypotheses are made concerning the sustainability trail to be followed in order to get the sustainable financial source.