Largeness of heart, i.e. either, first, Magnanimity, or generosity, and greatness of spirit, whereby he was disposed and emboldened to undertake great things. But this seems not so well to suit with the following resemblance. Or rather, secondly, Vastness of understanding; a most comprehensive knowledge of all things, both Divine and human; for this wisdom is the thing for which he is here commended, both in the foregoing and following words. Even as the sand that is on the sea-shore; which cannot be numbered or measured; and which, though it be so vast and comprehensive, yet consists of the smallest parts: and so it may note that Solomon's wisdom was both vast, reaching to all things; and most accurate, searching and discerning every small thing.
Related Commentaries of 1 Kings 4:29
1 Kings 4:29
29 And God gave Solomon wisdom and understanding exceeding much, and largeness of heart, even as the sand that is on the sea shore.