Whether the Intention Must Coincide with the Opening Takbīr
Must the intention coincide with the opening takbīr, or does an intention formed a short while before it suffice?
The intention need not coincide with the opening takbīr; it is valid for it to precede the takbīr by a short while, so long as no extraneous act such as speech or eating comes between them.
The intention must coincide with the takbīr, or precede it by a very short span joined to it; if it precedes by a long span or an interruption occurs, the prayer is not valid.
The intention must coincide with the opening takbīr: it must accompany the beginning of the takbīr and be sustained to its end.
The intention need not coincide with the opening takbīr; it may precede it by a short while so long as he does not revoke it, and coinciding with the takbīr is better.