That spark of holiness is transformed into a Jewish neshamah and replaces his previous identity as a non-Jew. He is a newborn person with no halachic connection to his past. Hashem shows particular love and solicitude for the ger , feeding and clothing him. Food is man's basic necessity. Out of recognition of the elevated essence of the ger, Hashem provides his essential necessities.
Clothing represents one's honor.
By providing clothing, Hashem honors the ger. On the one hand, we share an intrinsic affinity with that which the ger chose and accepted upon himself. Nevertheless, it is difficult to relate to the ger with a sense of total affinity since his embrace of Torah and mitzvos was voluntary and ours was by birth. Therefore the Torah could not merely exhort us to emulate Hashem in loving the ger since there is an impediment to actually fulfilling this command. We can appreciate and identify with the ger, for in our national experience we also were quasi-gerim, when we left Egypt and accepted the Torah.