RADAK
1.
(The address) in the singular refers to the people of Israel as a whole, for they were as one man in exile and of one mind.
אֵלִ֣י אֵ֭לִי לָמָ֣ה עֲזַבְתָּ֑נִי רָח֥וֹק מִֽ֝ישׁוּעָתִ֗י דִּבְרֵ֥י שַׁאֲגָתִֽי
Eli eli lamah azavtani rachok mishu'ati divrei sha'agati
My God, my God, why have You forsaken me? [You are] far from my salvation [and] from the words of my roaring.
1.
(The address) in the singular refers to the people of Israel as a whole, for they were as one man in exile and of one mind.
1.
My God, my God, for what purpose have You forsaken me...
David does not ask the question "Why?”. To him, Israel's disloyalty to God's Law is sufficient reason for all the pain it must now endure. However, God's promise, that the covenant of the Lord with Israel and the goals based thereon will nevertheless not cease to be, does justify the question as to the purpose of this utter despair which Israel senses as it is beset by the sufferings of exile.