Right. Works can be faked, speaking in tongues, for instance, can be faked ( lol ), prayer can be faked, so how will we know we can see the works Christ is referring to?
Actually, I find the answer is easier than some might think!
Anyone who is showing the opposite of these traits, especially the first few:
10 As it is written:
“There is no one righteous, not even one;
11 there is no one who understands;
there is no one who seeks God.
12 All have turned away,
they have together become worthless;
there is no one who does good,
not even one.”[b]
13 “Their throats are open graves;
their tongues practice deceit.”[c]
“The poison of vipers is on their lips.”[d]
14 “Their mouths are full of cursing and bitterness.”[e]
15 “Their feet are swift to shed blood;
16 ruin and misery mark their ways,
17 and the way of peace they do not know.”[f]
18 “There is no fear of God before their eyes.”[g]
The further you go away from these, the more you show the work of God through you. Those works defy the nature of sin in all of us, to where we DO seek after God, we gossip less, we choose not to poison people with our words, . . . in other words, we show these traits:
22 But the fruit of the Spirit is love, joy, peace, forbearance, kindness, goodness, faithfulness, 23 gentleness and self-control.
We become more in tune with the nature of God (while always maintaining the connection to God through Christ), rather than the nature we were born with.