The Three Jewels and the other objects of offerings like the old folks home or orphanages are all means for us to accumulate merits. The Three Jewels are supreme field of merits as they allow us to accumulate vast amount of merits.
The motivation behind any action is important because it determines whether the action is virtuous and meritorious. It also determines the amount of merits one will get from performing that action. Hence when we offer to the Three Jewels or other objects of offerings with bodhichitta motivation, we will obtain vast amount of merits compared to offering without bodhichitta motivation. The factors to consider when making offering are to offer with wisdom, compassion and skillful means.
Well-said dondrup. Your explanations are clear and precise. Offerings to Three Jewels undoubtedly will allow us to collect vast amount of merits as you mentioned. And the "Motivation" for making the offerings should be based on the thought of wanting to benefit others.
When we make offerings to Sangha, we are offering to the 3 Jewels. One may argue that the conduct of certain Sangha members sometimes leave devotees in suspects. They wonder whether they are offering to the right "Sangha" that hold his vows well and practicing in the correct way.
I found the guidelines as append below:
"Before making the offerings, the donor should meditate on the nine virtues of the Sangha. He or she should banish the idea of personal references or personal attitudes towards any individual monk, regarding the whole Sangha as the recipient...
...The intention to offer to the Sangha must focus on the virtues of the Buddha, Dhamma, and Sangha. Avoiding personal preferences, one should regard any monk as the representative of the Sangha. One should reflect thus: “He is a son of the Buddha, a representative of the Sangha, and therefore represents all the virtues of the Buddha’s first five disciples, the sixty Arahants who were the first missionaries, the one thousand Arahants of the Uruvela Forest, and other Arahants like Venerables S?riputta, Moggall?na, and Mah?kassapa.” Thus the supporter concentrates his mind on the virtues of the whole Sangha and, in this way, donates Sanghikad?na.
The commentary says, “Even in offering to immoral monks who only wear the robes around their necks, if one focuses the mind on the Sangha, it amounts to offering to the eighty great Arahants lead by the Venerables S?riputta and Moggall?na.” The good results one gets are the same. This is possible because the Noble Sangha, the true sons of the Buddha, by their powerful virtues, permeate influences and honour even today. The offering is beneficial not because of the monks’ immoral nature, but because of the purity of the Sangha.
Thus, a donor must focus his mind on the purity and power of the Buddha’s Noble Sangha. So even when offering to immoral monks, such good influences and benefits prevail if the mind is skilfully directed. So offering robes to immoral monks, amounts to offerings made to Arahants, past and present, who have completely eradicated the defilement."