Does the permissibility of combining prayers while traveling require the traveler to be actively moving (Sa'ir)?

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The opinion held by some, based on certain narrations concerning Ibn Umar and 'Ikrimah taking the explicit wording of those narrations, suggests that combination is only valid if the traveler is actively moving during the time of the first prayer, necessitating the delay until the time of the second prayer. However, the correct position, preferred by the majority of the companions of Imam Ahmad, is that it is permissible to advance the second prayer into the time of the first. Furthermore, strong evidence from Mu'adh ibn Jabal and Ibn Abbas shows the Prophet, peace be upon him, would combine prayers even when stationary (not actively moving) during the expedition of Tabuk. This proves combination is not restricted to a state of movement, as it is a concession of travel like Qasr and wiping over leather socks, though delaying is considered best for caution and exiting scholarly differences.