Tafsir of Maryam 19:87

ﻻ يملكون الشفاعة

None shall have the power of intercession, There will be no one who can intercede for them like the believers who intercede for each other. Allah says about them,

فما لنا من شفعين

وﻻ صديق حميم

Now we have no intercessors, nor a close friend. (26:100-101) Allah said,

إﻻ من اتخذ عند الرحمن عهدا

but such a one as has received permission (or promise) from the Most Gracious. This is a separate exclusion, which means, "But those who have taken a covenant with the Most Beneficent.'' This covenant is the testimony that none has the right to be worshipped but Allah, and upholding of its rights and implications. Ali bin Abi Talhah reported that Ibn Abbas said,

إﻻ من اتخذ عند الرحمن عهدا

(but such a one as has received permission (or promise) from the Most Gracious). "The promise is the testimony that none has the right to be worshipped but Allah, that the person accepts that all power and strength belong to Allah and he only places his hope with Allah alone.''