and His saying:

“If We willed, We could surely take away what We have revealed to you.” ⦗al-Isrāʾ 17:86⦘

and His saying:

“If they do not desist from what they are saying, a painful punishment will surely befall those among them who disbelieve.” ⦗al-Māʾidah 5:73⦘

and His saying:

“If he does not do what I command him, he will surely be imprisoned and will certainly become one of the humbled.” ⦗Yūsuf 12:32⦘

and His saying:

“Even if you were to bring them a sign, those who disbelieve would surely say, ‘You are nothing but falsifiers.’” ⦗al-Rūm 30:58⦘

and His saying:

“If help comes from your Lord, they will surely say, ‘We were with you all along.’” ⦗al-ʿAnkabūt 29:10⦘

and His saying:

“If We postpone the punishment for them for a fixed term, they will surely say, ‘What is holding it back?’” ⦗Hūd 11:8⦘

Such passages are plentiful; wherever the oath itself is not explicitly stated, it is nonetheless understood to have been elided and remains intended.