Translation of the verse 24 from Surah Al-Kahf : Number of verses 110 - - page 296 - Part 15.
Except (with the saying), "If Allah will!" And remember your Lord when you forget and say: "It may be that my Lord guides me unto a nearer way of truth than this."
Except [when adding], "If Allah wills." And remember your Lord when you forget [it] and say, "Perhaps my Lord will guide me to what is nearer than this to right conduct."
(18:24) except that Allah wills it." If ever you inadvertently utter anything like this, you should at once remember your Lord and say, "I hope that my Lord will guide me *24 in this matter with that thing which is nearest to the right way for me"
*24) This is a parenthetical clause which has been inserted here because of its relevancy to the preceding verse, in which it was asserted that the correct number of the Sleepers of the Cave is known only to Allah and a research into it is a useless task. Therefore one should refrain from investigating into unimportant things, nor enter into discussions about them. This has led to the instruction contained in the parenthetical clause for the benefit of the Holy Prophet and the Believers who have been told never to make a positive assertion like this: "L will do this thing tomorrow", for you do not know whether you will be able to do that thing or not: you have neither the knowledge of the unknown nor have full powers to do what you like. If ever inadvertently you utter anything like this, you should at once remember your Lord and say, "lnsha Allah." Besides this you do not know whether there will be any good for you in the thing about which you say, "1 will do this." It is possible that you may do another thing better than that. Therefore you should trust in God and say, "I hope that my Lord will guide me in this matter with that thing which is nearer to the right way for me."