“When you have finished prayer, exert yourself in supplication,” when what he has finished is of the same kind as what he is commanded to do? During prayer, he was already exerting himself in supplication, not free of it.

Furthermore, no Muslim has ever said that supplication after completing prayer is more emphatically prescribed or more powerful than supplication during it. Moreover, if His words meant, “Exert yourself in supplication,” there would have been no need for His words:

“And to your Lord alone direct your longing.”

For it is already known that supplication is to be directed to Allah alone.

It is thus clear that He commanded him to do two things: to strive in worship when free of his occupations, and to direct his longing to his Lord, not to anyone else. This is like His words:

“You alone we worship, and You alone we ask for help.”

His words, “You alone we worship,” correspond to His words, “Exert yourself.” And His words, “You alone we ask for help,” correspond to His words, “And to your Lord alone direct your longing.” Similar are His words:

“So worship Him and put your trust in Him.”

And His words:

“He is my Lord; there is no deity worthy of worship except Him. In Him I put my trust, and to Him is my return.”

And the words of Shuʿayb—peace be upon him:

“In Him I put my trust, and to Him I turn.”

Another example is the supplication reported for entering the mosque:

“O Allah, make me among the most honoured of those who turn to You, the nearest of those who draw near to You, and the best of those who ask of You and direct their longing to You.”

And the other report:

“To You we direct our longing and our deeds.”

This is because calling upon Allah, as mentioned in the Quran, takes two forms: invocation through worship, and invocation through petition and longing. Thus His words, “Exert yourself,” and “And to your Lord alone direct your longing,” encompass both forms of calling upon Allah. Allah Most High says:

“When the servant of Allah stood up calling upon Him, they almost crowded around him in throngs.”

And Allah Most High says:

“Whoever invokes another god besides Allah, for which he has no proof, his reckoning rests only with his Lord”—to the end of the verse.

There are many similar passages.