“Give a portion to seven, or even to eight.” Ecclesiastes 11:2 could well be about being generous to others so that when times are difficult then those other people will be able and willing to help in return. The general context contains verses about the uncertainty of life and how things may or may not work out for us (Ecc. 10:8, 9; 11:1; 4, 6). Given that, it is important that when things are going well for us that we share what we have with people in need, and hopefully, if the situation is ever reversed and we are the one in need, others will be willing to help us (cp. 2 Cor. 8:13). Also, it is important to diversify, because we do not know which things will be successful and which may not at all be.
When it comes to the phrase “seven, yes, even to eight,” the pattern “x then x+1” is a well-known pattern in the literature of the ancient Near East and so it makes sense that it would also be in the Bible. For example, the Bible has examples of “three things…four” (Prov. 30:15; 30:18, 21, 29; Amos 1:3, 6, 9, 11, 13; 2:1, 4, 6). It also has “six things…seven” (Job 5:19; Prov. 6:16); and “seven things…eight” (Ecc. 11:2). Although in the literature, sometimes the pattern places the emphasis on the second number because in some cases the second number is literal, usually the pattern is simply a way of expressing a large number. For example, when God is speaking of the sins of the countries in the Book of Amos and says, “for three sins, even for four” (Amos 1:3), He is using the literary device to point out that there are actually a very large number of sins.
Here in Ecclesiastes 11:2, the pattern, “seven, yes, even to eight,” is using the larger numbers of seven and eight to point out that it is wise to be generous to a large number of people because “you do not know what evil may happen on the earth,” and if the situation ever arises that you yourself are in need, there should be a large number of people who would be willing to help you because of your generosity to them.
Thus, this verse may be about being generous, and it may be about diversifying what you have, or it may contain both ideas.
“evil.” This is another example in Ecclesiastes of the word “evil” referring to a disaster of some kind and not a “moral evil.”