«كَلِمَةُ عَلَى لِلْإِلْزَامِ، وَأَصْلُهُ لِإِفَادَةِ مَعْنَى التَّفَوُّقِ وَالتَّعَلِّي»
Ala expresses obligation, while its origin involves being above or over something.
In a physical statement like “Zayd is on the roof,” it denotes location above a surface. In legal speech, an obligation is conceived as resting upon a person.
Consequently, an admission using “upon me” may acknowledge a payable debt. Expressions like “with me” or “in my possession” do not necessarily carry the same assertion of liability.