Hexagram 5, Xū (Waiting): Line 6 (top)
需卦上六 · 水天需 · 中文版
上六：入于穴，有不速之客三人来，敬之终吉。
The line (Legge)
The topmost SIX, divided, shows its subject entered into the cavern. (But) there are three guests coming, without being urged, (to his help). If he receive them respectfully, there will be good fortune in the end.
Small Image commentary
'Guests come unurged (to give their help), and if (the subject of the line) receive them respectfully, there will be good fortune in the end:' - though the occupant and the place are not suited to each other, there has been no great failure (in what has been done).
象曰：不速之客来，敬之终吉。虽不当位，未大失也。
In plain words
Falling into the pit; three uninvited guests arrive; treat them with respect and in the end there is good fortune. The Chinese idiom for an uninvited guest comes from this line, and the three are usually taken to be the three yang lines below. The top line is in the depth of danger; when waiting reaches its end, help comes from outside, and courtesy gets it out of trouble. The Small Image says that although it is not in its proper place, there is no great loss. The top line is actually yin in a yin place, so why the Small Image says otherwise is unclear; Zhu Xi marked it as uncertain.
Applying it to your situation
If, at the end of a long wait, what arrives is someone or something unexpected, this line suggests treating it courteously and not turning it away too quickly. Is there an uninvited change lately that deserves to be taken seriously?
Position
A broken (yin) line in the top place, which is a yin (even) place, so it is in its proper place. Its partner is line 3; one is yin and the other yang, so they respond to each other.
If this line moves
With this line moving alone, Xū changes into Hexagram 9 Xiǎo Chù (Small Taming). The Jiaoshi Yilin verse for this change (Chinese): 焦氏易林·需之小畜.
The hexagram
Hexagram 5 Xū (Waiting). The Judgment: Xu intimates that, with the sincerity which is declared in it, there will be brilliant success. With firmness there will be good fortune; and it will be advantageous to cross the great stream.
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English text: James Legge, The Yi King (Sacred Books of the East, vol. 16, 1882), public domain, as transcribed by the Chinese Text Project. Chinese: the received text. Offered for study and reflection, not as prediction. Plain-English readings and position notes by this site.