He gave them wisdom

Bible verses about Understanding
(From Forerunner Commentary)

Exodus 31:1-6
God personally appointed Bezaleel and Aholiab: "I have called by name"; "I have put." They were given favor by God to carry out this responsibility in His behalf for Israel. He gave them wisdom. The basic concept behind the Hebrew word translated wisdom is synonymous with the English word "skill." It is a word with wide-ranging applications.

 For instance, Proverbs 4:7, Solomon advises, "Wisdom is the principal thing; therefore get wisdom." In that context, it means skill in living, in common sense, in relationships with other people. We are to become skilled at doing these things.

The wisdom of Bezaleel and Aholiab is skill in supervising and teaching others how to do things, as well as being able to do intricate, artistic things themselves. Another way of putting it would be "strength of capacity" or even "expansion of their minds."
 In addition, God gave them understanding, which means "discernment." In this context of building the Tabernacle, it would mean being able to arrange or connect all the different parts.

God also increased their knowledge, which means "a particular acquaintance." Cunning works implies "inventiveness," having a mind that can look at something and say, "We need this kind of a tool to accomplish this task," and then produce the tool to make it. By inspiration, God added to natural ability so that they could execute God's design. He gave them skill far beyond their natural abilities.

John W. Ritenbaugh
The Holy Spirit and the Trinity (Part 6)