So show your love for the alien, for you were aliens in the land of Egypt. (Deuteronomy 10:19)
The literal commandment is to show love for the alien [Hebrew: ger- sojourner, foreigner].
Messiah explicitly affirmed this commandment numerous times when He spoke about the Law:
"Teacher, which is the great commandment in the Law?" And He said to him, " 'YOU SHALL LOVE THE LORD YOUR GOD WITH ALL YOUR HEART, AND WITH ALL YOUR SOUL, AND WITH ALL YOUR MIND.' This is the great and foremost commandment. The second is like it, 'YOU SHALL LOVE YOUR NEIGHBOR AS YOURSELF.' On these two commandments depend the whole Law and the Prophets." (Matthew 22:36)
Messiah repeatedly affirmed this commandment (Matthew 19:19, 22:39, Mark 12:31, Luke 10:27).
And who is our neighbor? In His parable of the good Samaritan, Messiah made it plain that strangers, foreigners... people who aren't like us... we should show them love and compassion.
This commandment pictures Messiah Who expressed the love of G-d to Israel but also to the Gentiles: those who were once foreigners to Israel and strangers to the covenants of promise (Ephesians 2:12).
By the loving work of Messiah believing Gentiles have been brought near and made a part of the commonwealth of Israel: the two groups have become one (Ephesians 2:13-14).
Messiah fulfilled this commandment by showing love to foreigners. One example was a Samaritan man who had leprosy:
While He was on the way to Jerusalem, He was passing between Samaria and Galilee. As He entered a village, ten leprous men who stood at a distance met Him; and they raised their voices, saying, "Jesus, Master, have mercy on us!" When He saw them, He said to them, "Go and show yourselves to the priests." And as they were going, they were cleansed. Now one of them, when he saw that he had been healed, turned back, glorifying God with a loud voice, and he fell on his face at His feet, giving thanks to Him. And he was a Samaritan. Then Jesus answered and said, "Were there not ten cleansed? But the nine--where are they? Was no one found who returned to give glory to God, except this foreigner?" (Luke 17:11-18)
Messiah expressed love to a Samaritan (a foreigner) by healing him. This was not some passive, intangible, touchy-feely, warm fuzzy feeling: this was an active action taken to alleviate the suffering of someone who was not His own.
Traditionally this commandment is understood to apply to converts to Judaism: Jews should show love to converts and not treat them harshly or disrespectfully as they learn, grow, and mature in their Jewish observance.
We are able to literally fulfill this commandment today and we should express profound concern and affection for strangers and aliens. Who knows if some day they will not become part of the family of G-d and no longer be strangers and aliens?
Two thousand years of bitter polemic between Jews and Christians has resulted in the change of the meaning of the Hebrew word ger from "sojourner" / "alien" to "convert". In many places and times the only foreigners who sojourned with the Jews were converts to Judaism! As a consequence, the traditional understanding and observance of the commandment shifted as well.
We have only to look at other passages of Scripture to find its true meaning:
Then she [Moses wife, Zipporah] gave birth to a son, and he [Moses] named him Gershom, for he said, "I have been a sojourner [ger] in a foreign land." (Exodus 2:22)
Unless Moses was a convert to the Midianite religion then he must have been a sojourner!
Here is another example:
"You shall not wrong a stranger [ger] or oppress him, for you were strangers [ger] in the land of Egypt." (Exodus 22:21)
Unless the Israelites were converts to the Egyptian religion then they must have only been sojourners in the land of Egypt.
We should consider the Emmaus road story from Luke 24. Messiah travelled incognito with two men who later recognized Him. We should show the love of G-d to those who sojourn through life with us. Perhaps at some point in their lives they will recognize that Messiah was with them (living through us) during that time.