References – AN 7.52: A Very Fruitful Gift 
“There are teachings about different levels of generosity (e.g. AN 7.52). Are there similar teachings about love or attachment?” Answered by Ajahn Pasanno and Ajahn Karuṇadhammo. [Generosity] [Goodwill] [Clinging] // [Dhamma] [Desire] [Teaching Dhamma] [Aggregates] [Mindfulness] [Relationships] [Spaciousness]
Love, Attachment, and Friendship [2019], Session 3, Excerpt 4
“When was the idea of merit [being like a celestial currency] incorporated into Buddhism?” Answered by Ajahn Amaro, Ajahn Karuṇadhammo and Ajahn Sundarā. [Merit] [History/Early Buddhism] // [Generosity] [Happiness]
Sutta: Iti 22: “Don’t belittle merit.”
Sutta: AN 7.52: Degrees of meritorious offerings.