A friend asks to borrow money
The suttas describe a good gift as one given with care, at the right time, freely, and without harming oneself or anyone else — which makes no a possible answer when the money would hurt you. They also count freedom from debt among the four kinds of happiness open to a householder, which applies to both of you. Between those is room for a decision only you can make. The speech teachings help with saying it: what is true, what is useful, and when. What the suttas do not do is judge your friend's need or set an amount.
What the suttas say
There are these five gifts of a true person. What five? They give a gift out of faith. They give a gift carefully. They give a gift at the right time. They give a gift with no strings attached. They give a gift without damaging themselves or others.
How to give, in five short qualities — including giving without harm to oneself, which answers the person giving beyond their means.
Where this stops: The results that follow each gift are framed as wealth and beauty in future lives; carry the five qualities, not the promised returns. It is about gifts of money or goods, not a measure of how much care to give a sick or ageing relative. Never use it to press someone to give out of guilt or pressure.
AN 5.148:1.1–1.3 · Gifts of a True Person
Pañcimāni, bhikkhave, sappurisadānāni. Katamāni pañca? Saddhāya dānaṁ deti, sakkaccaṁ dānaṁ deti, kālena dānaṁ deti, anuggahitacitto dānaṁ deti, attānañca parañca anupahacca dānaṁ deti.
Byagghapajja, these four things lead to the welfare and happiness of a gentleman in this life. What four? Accomplishment in initiative, protection, good friendship, and balanced finances.
Dīghajāṇu — the Buddha's household economics.
AN 8.54:2.1–2.3 · With Dīghajāṇu
Cattārome, byagghapajja, dhammā kulaputtassa diṭṭhadhammahitāya saṁvattanti diṭṭhadhammasukhāya. Katame cattāro? Uṭṭhānasampadā, ārakkhasampadā, kalyāṇamittatā, samajīvitā.
They don’t give a gift thinking, ‘When giving this gift my mind becomes clear, and I become happy and joyful.’ But they give a gift thinking, ‘This is an adornment and requisite for the mind.’
The ranking of motives for giving ends here — giving to adorn the mind rather than for a return.
Where this stops: The lower motives are not condemned; the sutta says each still bears fruit. Use it to point, not to grade.
AN 7.52:11.1–11.2 · A Very Fruitful Gift
Napi ‘imaṁ me dānaṁ dadato cittaṁ pasīdati, attamanatā somanassaṁ upajāyatī’ti dānaṁ deti; api ca kho cittālaṅkāracittaparikkhāraṁ dānaṁ deti.
Householder, these four kinds of happiness can be earned by a layperson who enjoys sensual pleasures, depending on time and occasion. What four? The happiness of ownership, using wealth, debtlessness, and blamelessness.
Money worry in the Buddha's own frame; blamelessness outweighs the rest.
AN 4.62:2.1–2.3 · Debtlessness
Cattārimāni, gahapati, sukhāni adhigamanīyāni gihinā kāmabhoginā kālena kālaṁ samayena samayaṁ upādāya. Katamāni cattāri? Atthisukhaṁ, bhogasukhaṁ, ānaṇyasukhaṁ, anavajjasukhaṁ.
“I can, Sīha,” said the Buddha. “A giver, a donor is dear and beloved to many people. This is a fruit of giving that’s apparent in the present life. Furthermore, good and true persons associate with a giver. This is another fruit of giving that’s apparent in the present life. Furthermore, a giver gains a good reputation. This is another fruit of giving that’s apparent in the present life. Furthermore, a giver enters any kind of assembly bold and self-assured, whether it’s an assembly of aristocrats, brahmins, householders, or ascetics. This is another fruit of giving that’s apparent in the present life. Furthermore, when a giver’s body breaks up, after death, they’re reborn in a good place, a heavenly realm. This is a fruit of giving to do with lives to come.”
General Sīha asks for results he can see for himself, and the Buddha names four; useful for someone who wants results they can check.
Where this stops: The sutta lists these as results of giving, not motives for it; do not frame generosity as a way to win liking or standing.
AN 5.34:2.1–6.2 · With General Sīha
“Sakkā, sīhā”ti bhagavā avoca: “dāyako, sīha, dānapati bahuno janassa piyo hoti manāpo. Yampi, sīha, dāyako dānapati bahuno janassa piyo hoti manāpo, idampi sandiṭṭhikaṁ dānaphalaṁ. Puna caparaṁ, sīha, dāyakaṁ dānapatiṁ santo sappurisā bhajanti. Yampi, sīha, dāyakaṁ dānapatiṁ santo sappurisā bhajanti, idampi sandiṭṭhikaṁ dānaphalaṁ. Puna caparaṁ, sīha, dāyakassa dānapatino kalyāṇo kittisaddo abbhuggacchati. Yampi, sīha, dāyakassa dānapatino kalyāṇo kittisaddo abbhuggacchati, idampi sandiṭṭhikaṁ dānaphalaṁ. Puna caparaṁ, sīha, dāyako dānapati yaṁ yadeva parisaṁ upasaṅkamati—yadi khattiyaparisaṁ yadi brāhmaṇaparisaṁ yadi gahapatiparisaṁ yadi samaṇaparisaṁ—visārado upasaṅkamati amaṅkubhūto. Yampi, sīha, dāyako dānapati yaṁ yadeva parisaṁ upasaṅkamati—yadi khattiyaparisaṁ yadi brāhmaṇaparisaṁ yadi gahapatiparisaṁ yadi samaṇaparisaṁ—visārado upasaṅkamati amaṅkubhūto, idampi sandiṭṭhikaṁ dānaphalaṁ. Puna caparaṁ, sīha, dāyako dānapati kāyassa bhedā paraṁ maraṇā sugatiṁ saggaṁ lokaṁ upapajjati. Yampi, sīha, dāyako dānapati kāyassa bhedā paraṁ maraṇā sugatiṁ saggaṁ lokaṁ upapajjati, idaṁ samparāyikaṁ dānaphalan”ti.