Rashi on Psalms
Forty years I quarreled with them and contended with them. [אקוט is] an expression of (Job 10: 1): “My soul quarrels (נקטה) with my life.” I strove with them for forty years to kill them in the desert, because I said, “They are of erring heart.”
Radak on Psalms
FORTY [years] that they angered me from the matter with the Spies until I said that they would remain in the desert for forty years. אקוט means “I saw them rebel”, and בדור refers to the generation of the desert.
Radak on Psalms
The mistake of their hearts and their hearts are negative so they didn't believe in Me.