"And he said, 'Board it, in the name of Allah be its course and its anchorage.'" Qatada said: Allah, may He be exalted, has clarified everything you should say when you ride on land and when you ride at sea. When you ride on land, you say: "Exalted is He who has subjected this to us, and we could not have [otherwise] subdued it." And when you ride at sea, you say: "In the name of Allah be its course and its anchorage."
Muhammad said: Whoever reads "In the name of Allah, its course (mujrāhā) and its anchorage (mursāhā)" with a damma on both mīms, the meaning is: By Allah is its setting in motion, and by Allah is its bringing to rest. It is said: The ship flowed (jarat).
﴿وَقَالَ ارْكَبُوا فِيهَا بِسْمِ اللَّهِ مجْراهَا وَمرْسَاهَا﴾ قَالَ قَتَادَةُ: قَدْ بَيَّنَ اللَّهُ ﷿ كُلَّ مَا تَقُولُونَ؛ إِذَا رَكِبْتُمْ فِي الْبَرِّ، وَإِذَا رَكِبْتُمْ فِي الْبَحْرِ؛ إِذَا رَكِبْتُمْ فِي الْبَرِّ قَلْتُمْ: ﴿سُبْحَانَ الَّذِي سَخَّرَ لَنَا هَذَا وَمَا كُنَّا لَهُ مُقرنين﴾ وَإِذَا رَكِبْتُمْ فِي الْبَحْرِ قُلْتُمْ: ﴿بِسم الله مجْراهَا وَمرْسَاهَا﴾.
قَالَ مُحَمَّد: من قَرَأَ: ﴿باسم اللَّهِ مُجْرَاهَا وَمُرْسَاهَا﴾ بِضَمِّ الْمِيمَيْنِ جَمِيعًا فَمَعْنَى ذَلِكَ: بِاللَّهِ إِجْرَاؤُهَا، وَبِاللَّهِ إِرْسَاؤُهَا؛ يُقَالُ: جَرَتِ السَّفِينَةُ