[13:15] Unto Him is the true prayer. And those on whom they call beside Him answer them not at all, except as he is answered who stretches forth his two hands toward water that it may reach his mouth, but it reaches it not. And the prayer of the disbelievers is but a thing wasted.
Explanation: It means (1) God alone is worthy of worship; (2) it is praying to God alone that can be useful or beneficial for man; (3) the Voice of God alone rises in support of truth; and (4) the Voice of God alone must prevail.
(courtesy Amjad Tariq Sydney)