Negative and Positive statements of God's attributes

"The attributes of God are variously distinguished by divines; some distinguish them into negative and positive, or affirmative: the negative are such as remove from him whatever is imperfect in creatures; such are infinity, immutability, immortality, &c. which deny him to be finite, mutable, and mortal; and, indeed it is easier to say what God is not, than what he is: the positive, or affirmative, are such as assert some perfection in God, which is in and of himself; and which in the creatures, in any measure, is from him, as wisdom, goodness, justice, holiness, &c. but the distinction is discarded by others; because all negative attributes some positive excellency is found." -John Gill, The Body of Divinity, Pg. 34-35

For example, God is infinite which means he is timeless. Some Calvinist and Catholics teach that we can only speak of God in the negative statements. This makes no since. For one thing, if we can only speak of God in the negative only and not in any positive statements as well then how can we know him? I mean we know what he is not, but what is God as the WCF says.