"It is He who made the earth subservient for you," meaning: He made traversing it easy for you and subjugated it to you. "So walk," meaning: proceed, "in its paths," meaning: its ways. This is the interpretation of al-Hasan and Mujahid.
﴿هُوَ الَّذِي جَعَلَ لَكُمُ الأَرْضَ ذلولا﴾ أَيْ: سهَّل لَكُمُ السُّلوك فِيهَا وذلَّلها لكم ﴿فامشوا﴾ فامضوا ﴿فِي مناكبها﴾ طُرُقِهَا؛ وَهُوَ تَفْسِيرُ الْحَسَنِ وَمُجَاهِدٍ