When Allah's Messenger ﷺ came near Safa, he said: ﴿اِنَّ الصَّفَا وَالْمَرْوَةَ مِنْ شَعَائِرِ اللّٰهِ﴾ اَبْدَأُ بِمَا بَدَأَ اللّٰهُ بِهٖ “Indeed, as-Safa and al-Marwah are among the symbols of Allah. I begin with what Allah began with.”

Then the Prophet ﷺ began with Safa. He climbed it until he saw the House of Allah, then faced the qiblah and, declaring the oneness and greatness of Allah, said these words:

لَآ اِلٰهَ اِلَّا اللّٰهُ وَحْدَهٗ لَا شَرِيْكَ لَهٗ ، لَهُ الْمُلْكُ وَلَهُ الْحَمْدُ وَهُوَ عَلٰى كُلِّ شَيْءٍ قَدِيْرٌ لَآ اِلٰهَ اِلَّا اللّٰهُ وَحْدَهٗ اَنْجَزَ وَعْدَهٗ وَنَصَرَ عَبْدَهٗ وَهَزَمَ الْاَحْزَابَ وَحْدَهٗ

There is no deity except Allah; He is alone and has no partner. His is the dominion and His is all praise, and He has full power over all things. There is no deity except Allah alone. He fulfilled His promise, helped His servant, and alone defeated the (opposing) groups.

Then he made supplication in between, saying it like this three times. The hadith is long, and it also mentions that the Prophet ﷺ did at Marwah just as he did at Safa.

Sahih Muslim, no. (1218), the wording is his, Sunan Abi Dawud, no. (1905), Sunan Ibn Majah no. (3047). The verse is from Surah al-Baqarah (2/158).