The words regarding parents in the Decalogue read as follow, “Honor your father and your mother.” And it entails a blessing for obedience, “that your days may be long in the land that YHWH your God is giving you.” (Exo 20.12) At that time, the Israelites were still in the desert (they were in Mt. Sinai at that time) and they had not reached the land of Canaan yet. Hence the blessing was a promise (Apostle Paul noted that it was the first commandment with a promise, Eph 6.1).
The set of commandments was repeated in Deuteronomy, and this particular commandment came with a slightly different wordings for the blessing: “that your days may be long, and that it may go well with you in the land that YHWH your God is giving you.” (Deu 5.16) The land was the land that YHWH was going to give to them and it was the land of Canaan.
Hence it was appropriate for apostle Paul to truncate the promise when he quoted the commandment in his letter to the Ephesians: “Honor your father and your mother, that it may go well with you and that you may live long in the land.” (Eph 6.2-3) The missing phrase is ‘that YHWH your God is giving you.” The specificity of the land in Exodus-Deuteronomy then was universalized by Paul. That’s why some translations (e.g., KJV, CEV, LAI-ITB) put the word ‘earth’ instead of ‘land’ (ge- in Greek could mean both) to emphasize further the universalization of the Exodus-Deuteronomy promise.
And what he did implicitly here he did explicitly elsewhere. In his letter to the Romans, Paul wrote that the promise to Abraham and his offspring was that he (Abraham) would be the heir of the world (kosmos — Rm 4.13). The original promise was not for Abraham to inherit the world, but the land (gen – Gen 12.1). Again, the scope of the promise was universalized by Paul.