The Jewish people consider charity to the poor to be such a central act of righteousness that in Hebrew, the term “righteousness (tzedakah),” is often used synonymously to mean gifts given to the poor. Our Master assumed His disciples will give generously. He did not say “if you give to the poor” but “when you give to the poor."
So when you give to the poor, do not sound a trumpet before you, as the hypocrites do in the synagogues and in the streets, so that they may be honored by men. Truly I say to you, they have their reward in full. (Matthew 6:2)
Announcing charity with trumpets simply means giving alms in public, that is, at the donation box where everyone can see the philanthropist perform the noble deed. Giving charity “in the streets” probably refers to conspicuously distributing alms to beggars. The word “hypocrite” did not imply insincerity or a double standard as it does in English today. The “hypocrite” of the Gospels is anyone who performs religious duties for the sake of being admired by others.
Yeshua told His disciples to do their giving in secret so that they will receive a reward from their Father in heaven:
But when you give to the poor, do not let your left hand know what your right hand is doing, so that your giving will be in secret; and your Father who sees what is done in secret will reward you. (Matthew 6:3-4)
Those who make contributions in public have already received their reward in the form of public admiration. They receive no reward from God because their acts of righteousness were never sincere.
Note the important principle. Contrary to popular theology which teaches that a man’s righteous acts are only regarded as filthy rags before the LORD, the Master assumes that sincere acts of righteousness such as giving alms do achieve merit with God. The man who gives charity lays up treasure in heaven—that is to say, he merits reward from God. “Will He not render to man according to his work?” (Proverbs 24:12).
The Talmud praises a man who gives charity in secret, saying, “A man who gives charity in secret is greater than Moses our Teacher.” The sages taught that giving charity in secret turned away God’s displeasure with a man, as it says in Proverbs 21:14, “A gift in secret subdues anger.”
The Talmud says that ideally “a man gives without knowing to whom he gives, and the beggar receives without knowing from whom he receives.” Reb Yannai once saw a man giving a zuz to a poor man in the marketplace. He said, “It would be better not to have given him anything rather than to have given to him publicly and shamed him.” Moreover, the Talmud considers “a man who tithes his produce in secret,” as worthy of a reward in the World to Come.