Hadithcore
Al-Adab Al-Mufrad, 215
sahih· Al-Albani

Jabir ibn 'Abdullah al-Ansari reported that the Prophet, (ﷺ), said, "Whoever has a favour done for him should repay it. If he cannot find anything he can use to repay it, he should praise the one who did it. When he praises him, he thanks him. If he is silent, he is ungrateful to him. If someone adorns himself with something he has not been given, it is as if he was wearing a false garment."

حَدَّثَنَا سَعِيدُ بْنُ عُفَيْرٍ قَالَ‏:‏ حَدَّثَنِي يَحْيَى بْنُ أَيُّوبَ، عَنْ عُمَارَةَ بْنِ غَزِيَّةَ، عَنْ شُرَحْبِيلَ مَوْلَى الأَنْصَارِ، عَنْ جَابِرِ بْنِ عَبْدِ اللهِ الأَنْصَارِيِّ قَالَ‏:‏ قَالَ النَّبِيُّ صلى الله عليه وسلم‏:‏ مَنْ صُنِعَ إِلَيْهِ مَعْرُوفٌ فَلْيُجْزِئْهُ، فَإِنْ لَمْ يَجِدْ مَا يُجْزِئُهُ فَلْيُثْنِ عَلَيْهِ، فَإِنَّهُ إِذَا أَثْنَى فَقَدْ شَكَرَهُ، وَإِنْ كَتَمَهُ فَقَدْ كَفَرَهُ، وَمَنْ تَحَلَّى بِمَا لَمْ يُعْطَ، فَكَأَنَّمَا لَبِسَ ثَوْبَيْ زُورٍ‏.‏

References2 variants
In-Book Reference
Book 10, Hadith 4
English Reference
Book 10, Hadith 215