Exodus 25:2

"Speak unto the children of Israel, that they bring me an offering: of every man that giveth it willingly with his heart ye shall take my offering."

Cross References (ranked by relevance)

2 Corinthians 9:7 13

Every man according as he purposeth in his heart, so let him give; not grudgingly, or of necessity: for God loveth a cheerful giver.

Nehemiah 11:2

And the people blessed all the men, that willingly offered themselves to dwell at Jerusalem.

Ezra 2:68

And some of the chief of the fathers, when they came to the house of the LORD which is at Jerusalem, offered freely for the house of God to set it up in his place:

Ezra 1:6

And all they that were about them strengthened their hands with vessels of silver, with gold, with goods, and with beasts, and with precious things, beside all that was willingly offered.

Ezra 7:16

And all the silver and gold that thou canst find in all the province of Babylon, with the freewill offering of the people, and of the priests, offering willingly for the house of their God which is in Jerusalem:

Ezra 3:5

And afterward offered the continual burnt offering, both of the new moons, and of all the set feasts of the LORD that were consecrated, and of every one that willingly offered a freewill offering unto the LORD.

Psalm 110:3

Thy people shall be willing in the day of thy power, in the beauties of holiness from the womb of the morning: thou hast the dew of thy youth.

Numbers 18:24

But the tithes of the children of Israel, which they offer as an heave offering unto the LORD, I have given to the Levites to inherit: therefore I have said unto them, Among the children of Israel they shall have no inheritance.

Judges 5:9

My heart is toward the governors of Israel, that offered themselves willingly among the people. Bless ye the LORD.