Se presentaron algunos beduinos [ante ti, ¡Oh, Mujámmad!] pidiéndote permiso para no ir a luchar sin excusa válida, pero los [hipócritas] que mintieron a Dios y a Su Mensajero se quedaron sin excusarse siquiera. A estos incrédulos Dios les infligirá un castigo doloroso.
Explicación:
Both readings contain the possibility that these people had genuine excuses, though the second (active participle of form IV) is more indicative of that. They can also be interpreted to mean they were making false excuses, and the first (from form II or VIII) is more indicative of that; in that case, the subsequent phrase 'those who lied' refers to the same people [al-Alusi].