﴿ وَإِن كَانَ كَبُرَ عَلَيْكَ إِعْرَاضُهُمْ فَإِنِ ٱسْتَطَعْتَ أَن تَبْتَغِىَ نَفَقًۭا فِى ٱلْأَرْضِ أَوْ سُلَّمًۭا فِى ٱلسَّمَآءِ فَتَأْتِيَهُم بِـَٔايَةٍۢ ۚ وَلَوْ شَآءَ ٱللَّهُ لَجَمَعَهُمْ عَلَى ٱلْهُدَىٰ ۚ فَلَا تَكُونَنَّ مِنَ ٱلْجَٰهِلِينَ ﴾

“And if it distress thee that those who deny the truth turn their backs on thee - why, then, if thou art able to go down deep into the earth or to ascend a ladder unto heaven in order to bring them a [yet more convincing] message, [do so;] but [remember that] had God so willed, He would indeed have gathered them all unto [His] guidance. Do not, therefore, allow thyself to ignore [God's ways].”

Please check ayah 6:36 for complete tafsir.