Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 6 · Calendar, Muhurta Elements
कालमानं मुहूर्ताङ्गानि च
जन्मराशेर्गुरुः श्रेष्ठः स्वायगोऽध्यस्तगो न चत् ।विध्यतेंत्याष्टखांबुत्रिगतैः खेटैर्मुनीश्वर ॥ २७५ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 56, verse 275.
Jupiter is best from the birth sign in the 2nd, 11th, 5th and 7th, if it is not blocked. It is blocked by planets standing in the 12th, 8th, 10th, 4th and 3rd, O chief of sages.
Simple meaning: Jupiter is good in the 2nd, 5th, 7th and 11th, unless planets in blocking places stop it.
जन्मभादासुताष्टांकांत्यायेष्विष्टो भृगोःसुतः ।
Venus is good in most places from the birth sign, unless planets in blocking places stop it.
न ददाति शुभं किंचिद्गोचरे वेधसंयुते ।
A blocked planet in transit gives nothing good, so check the blocking first.
वामभेदविधानेन दुष्टोऽपि स्याच्छुभङ्करः ।
Reverse blocking can turn a bad planet good. Looks of good or bad planets reverse the result.