"Take heed that you do not do your charitable deeds before men, to be seen by them. Otherwise you have no reward from your Father in heaven. Therefore, when you do a charitable deed, do not sound a trumpet before you as the hypocrites do in the synagogues and in the streets, that they may have glory from men. Assuredly, I say to you, they have their reward. But when you do a charitable deed, do not let your left hand know what your right hand is doing, that your charitable deed may be in secret; and your Father who sees in secret will Himself reward you openly.” Matthew 6:1-4
The passage ends with Jesus speaking about being rewarded for giving. Is there a reward for giving? Yes, and no.
First, the Yes. There is a reward for giving, but let us understand that God rewards believers not so much for giving, per se, but for being generous. Giving out of one’s abundance requires little or no generosity (Luke 21:4) Remember that God looks not merely on outward deeds but on inward attitudes of the heart.
Second, the No. A popular false teaching promulgated by the prosperity cults teaches people to give in order to get. This is completely unbiblical and therefore false. It is superstitious and self-serving. And it does not work. God is never obligated to give us anything. He gives because of His grace, not because we give some money so we can receive more money.
Give because you have already received so much (everything) from God. Give to bless other people, preferably in ways that they will not know who gave what they have received. And do not give in hopes of receiving wealth in return.