The relationship between God and the Israelites began with profound joy, only to fracture into a tragic tale of betrayal and moral decay. God's early connection with the nation is likened to a traveler stumbling upon grapes in a barren, dry wasteland. Just as finding fresh fruit in a desolate desert brings immense, unexpected happiness [אבן עזרא, רד״ק], the Israelites were incredibly precious to God when they first formed a nation in the wilderness [רש״י, מצודת דוד]. Grapes are a purely natural fruit, unmixed with other species, representing the early purity of the Israelites and their distance from immorality when they left Egypt [מלבי״ם, אברבנאל]. Furthermore, just as grapes uniquely provide both food and drink, the Torah given in the desert completely sustained the nation, satisfying all their spiritual needs [אברבנאל].
This early affection is also compared to discovering the very first fig to ripen on a tree [רש״י, מצודת ציון]. A person who finds the first fruit, flawless and rare, rejoices deeply [מצודת דוד, מלבי״ם]. In the same way, God found great joy in the patriarchs of the nation, as they were the first to accept His divine light in an otherwise dark world [מלבי״ם, אברבנאל].
However, this joy was painfully short-lived [אבן עזרא]. The tragedy unfolded at Baal Peor. Rather than focusing on earlier failures like the Golden Calf, the rebuke specifically highlights Baal Peor because the core issue there was physical adultery. This physical lust served as the direct gateway and preparation for spiritual betrayal and idol worship [אברבנאל, מלבי״ם].
The Israelites actively separated themselves from God [רש״י, מצודת ציון] and dedicated their lives to a shameful idol. False worship is described as a shame because dedicating oneself to idols ultimately brings nothing but disgrace and humiliation to the worshiper [רש״י, מצודת ציון, רד״ק]. Consequently, the people became completely detestable. Commentators offer two ways to understand the depth of this ruin. One perspective explains that the nation became an abomination because of their intense lust for the women of Moab and Midian, which dragged them into deep impurity [רש״י, אבן עזרא, אברבנאל]. Another perspective highlights a tragic parallel to God's initial affection: the Israelites became as disgusting and repulsive in God's eyes as they were once deeply and intensely loved by Him [מצודת דוד, רד״ק, ביאור שטיינזלץ].