The example of those who spend their money in the cause of God is like the
example of a grain that sprouts out seven spikes, with a hundred grains in each spike;
God multiplies man
ifold for whom He wills. God is Immense, Knowledgeable.

The act of dedicating one's self and one's resources to the cause of God is undoubtedly the highest form of devotion to God. Those who do so are promised the highest rewards.

The words in 2:261 reveal the infinite generosity endowed by God on such loyal servants. We are also told about this reward in the following words:

Those who believed, emigrated and strove in the cause of God with their money and themselves hold the greatest rank with God. Those are the winners. 9:20

No talk is better than that which preaches the way to God:

Who is better spoken than one who invites to God, does good deeds, and says, "I am one of the Submitters"? 41:33

The command to devote and dedicate ourselves and our money to the cause of God is also found in (Sura 22, verse 67) and (Sura 28, verse 87).

The Quran also provides the optimum method of preaching and inviting to God:

Invite to the path of your Lord with wisdom and advice, and debate with them in the best possible manner. 16:125