Two men once prayed at length before Rabbi Eliezer. The first stretched his Amidah far beyond the usual length, swaying and adding private petitions until the congregation grew restless. The second raced through his words so quickly that he finished almost before he started.
Rabbi Eliezer's students came to him afterward, troubled. "Master, the first man was praying too long. And the second was praying too briefly. Both seemed wrong."
Rabbi Eliezer answered them quietly.
"The one who prayed long," he said, "was not praying longer than Moses, who once stood before God for forty days and forty nights on the mountain, pleading for Israel after the sin of the calf (Exodus 34:28). If Moses prayed for forty days, who are we to criticize a man for praying a few extra minutes?
"And the one who prayed short was not praying shorter than Moses either, who, when his sister Miriam was struck with leprosy at the edge of the camp, cried out only five Hebrew words — El na refa na lah, 'Please, God, heal her please' (Numbers 12:13). That prayer was the length of a breath, and God accepted it."
The Exempla preserves Rabbi Eliezer's teaching because it dissolves a false argument. The right length of a prayer is not fixed. What matters is the inward match: a long prayer that refuses to leave God's side, or a short prayer in a moment so urgent there is no room for extra words. Both have a prophet's precedent.
(From The Exempla of the Rabbis, Moses Gaster, 1924, no. 185, based on Berakhot 34a.)