The precious promise in this verse has been an inspiration to the faithful down through the centuries. It becomes even more amazing when attention is paid to the original Greek language in which it was written.
Abiding implies a close personal fellowship with someone; in this case, the personal, loving Lord Jesus: "As the Father hath loved me, so have I loved you: continue ye in my love" (v. 9). Such an abiding on our part will be evidenced by obedience, love for Him and for the brethren, and joy (vv. 10-14). Our minds and hearts will be in total harmony with His, guided by such a walk and His words.
"Ye shall ask" does not carry the proper force in English. This is a command in the imperative mode in Greek--a challenge, if you will. He challenges us to "ask what ye will" (literally, "whatever ye desire") and see Him faithful. Desire speaks of something different than need, indeed it speaks of an "inclination." He is not afraid we will ask for selfish inclinations, for if we "abide" in Him, our desires are His desires, and we will naturally ask for those things which glorify Him. "Herein is my Father glorified, that ye bear much fruit; so shall ye be my disciples" (v. 8).
Notice the word "done," which in Greek stems from the word meaning "to come into existence." God will answer our unselfish prayers, even if He has to transcend natural law or even create something to do so. He even challenges us to "ask" without hesitation, as implied by the Greek construction.
If we meet the condition of "abiding" in Him, as a branch "abides" in the vine (vv. 1-5), He will place in us the desire to bring forth much fruit (v. 5) to His glory and to our everlasting delight. JDM