Many phrases that discuss tzedakah are written in double. For example, (14:22) עשר תעשר, תתן נתן (15:10), ידך את תפתח פתוח (15:8), and the reward is also doubled as it states (15:4) אלקיך 'ה יברכך ברך כי. The Kli Yakar (14:22) writes, "All phrases about tzedakah are doubled because one can give charity with one's hand and say kind words with one's mouth. This is the meaning of תפתח פתוח, open your hand and open your heart. For both aspects of tzedakah, he will be rewarded. Therefore, it states יברכך ברך כי."
The Gemara (Bava Basra 9:) states, פרוטה הנותן א"בי מתברך בדברים והמפייסו ברכות בשש מתברך לעני ברכות, "One who gives a prutah to the poor receives six brachos, and if he says kind words to appease him, he is blessed with eleven brachos." (Tosfos explains that if he does both, he gives tzedakah and says kind words, he will receive eighteen brachos.)
The Rambam (Matnas Aniyim 10:4-5) writes, "Whoever gives tzedakah with a melancholy face, and he looks down to the ground, even if he gave him a thousand gold coins, he lost his reward. Rather, give money with a kind face and with joy and moan together with him over his tzar, as it states (Iyov 30:25) לא אם לאביון נפשי עגמה יום לקשה בכיתי, 'Whether I did not weep for one who had a difficult time, or whether my soul was [not] grieved for the needy.' Speak with him words of comfort and chizuk, as it states (Iyov 29:13) אלמנה ולב ארנן, 'I would make the widow's heart sing for joy.' If a poor person asks from you, and you have nothing to give him, appease him with your words. It is forbidden to shout at the poor or to raise your voice at him because his heart is broken and humble. It states (Tehillim 51:19) תבזה לא אלקים ונדכה נשבר לב, 'A broken and crushed heart, Hashem will not despise.' And it states (Yeshayah 57:15) להחיות נדכאים לב ולהחיות שפלים רוח, 'to revive the spirit of the humble and to revive the heart of the crushed.' Woe to the person who shames the poor. Woe is to him. Rather, be like his father, both with compassion and with words, as it states (Iyov 29:16) לאביונים אנכי אב, 'I was a father to the needy.'"
It states, (15:11) כן על הארץ מקרב אביון יחדל לא כי ולאבינך לעניך לאחיך ידך את תפתח פתח לאמר מצוך אנכי בארצך, "For there will never cease to be needy within the land. Therefore, I command you, saying, you shall surely open your hand to your brother, the poor, and the needy in your land." Rebbe Yisrael of Ruzhin zt'l says that the pasuk can be read as מצוך אנכי כן על תפתח פתח לאמר as follows, "לאמר מצוך אנכי, I command you to tell the poor, תפתח פתח the day will yet come when you will be the one who is opening up your hand to help the poor."
