Theodoret of Cyrus
The phrase "and his heart was lifted up" is mentioned by the author not as a form of condemnation but as an expression of admiration, as he goes on to say "in the ways of the Lord, and out of the oak-trees from the land of Judah."
And when his heart had taken courage for the ways of the Lord, he took away also the high places and the groves out of Juda.
וַיִּגְבַּ֥הּ לִבּ֖וֹ בְּדַרְכֵ֣י יְהוָ֑ה וְע֗וֹד הֵסִ֛יר אֶת־הַבָּמ֥וֹת וְאֶת־הָאֲשֵׁרִ֖ים מִיהוּדָֽה׃
One Church Father comments on this verse
The phrase "and his heart was lifted up" is mentioned by the author not as a form of condemnation but as an expression of admiration, as he goes on to say "in the ways of the Lord, and out of the oak-trees from the land of Judah."
Passages read together with this verse.