Deuteronomy 16:17
Every man shall give as he is able, according to the blessing of the Lord thy God which he hath given thee.
Cross-reference
Deuteronomy 16:10 gives the same principle for the Feast of Weeks: give a freewill offering according to God's blessing, directly paralleling the general rule here.
Mark 12:41-44 illustrates this principle: the widow gave all she had, demonstrating giving according to ability even in poverty.
2 Corinthians 8:12 directly echoes this principle: giving is acceptable according to what one has, not according to what one does not have.
In 1 Chronicles 21:24, David refuses to offer that costs nothing, complementing the principle here of giving as able—both stress heartfelt, costly offerings.
Matthew 5:23 adds the need for reconciliation before offering, expanding on the act of bringing gifts commanded here with a relational condition.
Exodus 25:2 similarly calls for a freewill offering from those whose hearts are moved, paralleling the principle of giving willingly according to blessing.
Leviticus 27:8 also bases giving on what a person can afford, offering a parallel principle for valuations of vows according to ability.
Ezekiel 46:5 specifies grain offerings for feasts, providing a detailed regulation that mirrors the general command here to give at the appointed times.
2 Corinthians 9:7 adds the heart attitude: give cheerfully and willingly, not reluctantly — complementing the call to give according to ability.