Translation:

24. O ye who believe! give your response to Allah and His apostle when He calleth you to that which will give you life; and know that Allah cometh in between a man and his heart and that it is He to whom Ye shall (all) be gathered.

Notes (Tafseer)

1196. There are two points to note. (1) Note that after Allah and His Messenger are mentioned, the pronoun and verb in the next clause are singular: everything that Allah's Messenger put forward as an injunction came by inspiration from Allah: the Messenger made his will coincide completely with Allah's will. (2) We are asked actively to give our response in deed and life to the call of duty and conscience, for that call leads to real life, the life eternal, even though it may apparently mean in this world the loss of things that make life dear or the loss of life itself. If we refer this to Jihad, i.e., fighting in and for the Cause, both literally and metaphorically, the meaning becomes quite clear.

1197. If the human heart is refractory and refuses to obey the call of Allah, that is not the end of the matter. Allah has to be reckoned with. The refusal may be because there was some pet human scheme which the heart of man was not willing to give up for Allah's Cause. Will that scheme come to fruition by refusing to serve the higher Cause? By no means. Man proposes, but God disposes. If the scheme or motive was perfectly secret from men, it was not secret from Allah. The heart is the innermost seat of man's affections and desires: but Allah intervenes between man and his heart.