يَٰوَيۡلَتَىٰ لَيۡتَنِى لَمۡ أَتَّخِذۡ فُلَانًا خَلِيلًا
"Ah! woe is me! Would that I had never taken such a one for a friend!<br/>
O woe to me! (yaa waylataa: the [final] alif stands in place of the [first person singular] possessive yaa', yaa waylatee, meaning '[alas] for my destruction!') Would that I had not taken so and so, in other words, [that] Ubayy, as friend!