The needle-eye is too small to hold the thread.

针眼太小线穿不进去。

《新英汉大辞典》

From the valley below, each pier and mast merge to look like a single needle with an elongated eye: Foster's drawings, in fact, depict a thread piercing the eye of a needle.

WSJ: A Concrete Ribbon Through the Clouds | Millau Viaduct | Masterpiece by Joseph Giovannini

WSJ's Gautam Naik reports these micro-sculptures are small enough to fit inside the eye of a needle.

WSJ: AHEAD OF THE TAPE: Family Dollar Still Has Some Buying Points

It is easier for a camel to pass through the eye of a needle than for a rich man to enter the Kingdom of Heaven.

BBC: Number free facts