וַתֵּ֣לֶד בֵּ֔ן וַיִּקְרָ֥א אֶת־שְׁמ֖וֹ גֵּרְשֹׁ֑ם כִּ֣י אָמַ֔ר גֵּ֣ר הָיִ֔יתִי בְּאֶ֖רֶץ נָכְרִיָּֽה׃ (פ)
그가 아들을 낳으매 모세가 그 이름을 게르솜이라 하여 가로되 내가 타국에서 객이 되었음이라 하였더라
Rashbam
בארץ נכריה. The meaning of the name Gershom, i.e. a stranger in a distant land.
Sforno
גר הייתי בארץ נכריה. A stranger in a land which is not my birthplace.
Or HaChaim
גר הייתי, "I was (used to be) a stranger, etc." The Torah deliberately phrases this in the past tense because the Torah reports events as of the time the Torah was written (at that time Moses could speak of his being a stranger in the past tense, whereas at the time the baby was born he was still a stranger in Midian). Alternatively, the words may be understood along the lines of Psalms 119,19: גר אנכי בארץ, "I am only a stranger on earth." Righteous people in this world are merely strangers, they have no permanent abode. Moses meant that ever since he was born he had merely been a stranger in a foreign land, seeing he had not been raised in his parents' home or shared his youth with his siblings.