The determination that is unwavering and keeps under control the fickle mind, the verve (or willpower) and sensuous inveigles and reactions to them; which is steadied by practicing Yog, such determinations are Satwik, O’ Partha!
Indeed, determination should be firm. Firmness does not connote to sticking to decision taken, which may be corrected later on, but strength of character, resilience and grit that allows one to comeback after failures and stick to objective goals till met. Worth quoting Kathopnishad here: “Uttishthat Jagrut, Prapya Varrannibodhat i.e. Arise, awake, and do not stop till the goal is met.” Stay firm to utilitarian deeds of humanity. Often people are afraid to reverse their decision as society does not see this positively, especially in politics. Firmness in character, and objectives is required. Procedures may change with the goals intact.
But the determination that is driven by desires of material gains and blinded by religious fervour, driven by the subjective contexts; and driven by fruit-bearing expectations, such determinations, O’ Arjun! are Rajasik!<
Determination that causes frightening dreams, fear, dismay, grief, whine, delusion in vainglory leads to lack of conscience in thoughts and acts and yet unable to let one free from such thoughts, such intellect, is for sure, Tamasik, O’ Arjun! (For them purification by thoughts and minds is required.)