Not by an unbridled passion, but in zeal for God's honour, and by the direction of God's Spirit, to signify to the people, that the covenant between God and them contained in those tables was broken and made void, and they were now quite cast out of God's favour, and could expect nothing from him but fiery indignation and severe justice. See Poole on "Exodus 32:19".
Related Commentaries of Deuteronomy 9:17
Deuteronomy 9:17
17 And I took the two tables, and cast them out of my two hands, and brake them before your eyes.