1. Who is Shri Radha?

The most selfless and most intense love for Shri Krishna is Shri Radha.
For material beings, like us, our powers are not personified. e.g. one strength, compassion etc cannot take a form and become separate from us. That is not the case for Shri Krishna.
All powers of Shri Krishna are personified. Shri Krishna's power of love, Shri Radha, descended on Earth at the end of Dvapar yug in the month of August. Barsana is a village in Mathura district in U.P. India. The King of Barsana was Vrishbhanu. She blessed Vrishbhanu and his wife Mother Kirti by appearing in their house as their daughter.
वंदे वृन्दावनानंदां राधिकां परमेश्वरीम्।
गोपिकां परमां शुद्धा ह्लादिनी शक्तिरूपिणीम्॥
vaṁde vr̥ndāvanānaṁdāṁ rādhikāṁ parameśvarīm।
gopikāṁ paramāṁ śuddhā hlādinī śaktirūpiṇīm॥
"Shri Radha is the Supreme entity with none beyond Her."
Once some God realized Brahm Gyanis asked the same question:
कः परमो देवः कुतो मृत्योर्भवेति कस्य ज्ञानेनाखिलं विज्ञातं भवति ।
kaḥ paramo devaḥ kuto mr̥tyorbhaveti kasya jñānenākhilaṁ vijñātaṁ bhavati ।
“Who is that Supreme Brahm, knowing whom gives you the complete knowledge of everything?"
The Vedas replied –
कृष्णो ह वै पर्मं दैवतं गोविन्दान्मृत्युर्विभेति ।
गोपिजनवल्लभज्ञानेन तज्ज्ञातं भवति ।
तस्मात्कृष्ण एव परो देवस्तंध्यायेत् तं रसयेत् तं भजेत्॥
kr̥ṣṇo ha vai parmaṁ daivataṁ govindānmr̥tyurvibheti ।
gopijanavallabhajñānena tajjñātaṁ bhavati ।
tasmātkr̥ṣṇa eva paro devastaṁdhyāyet taṁ rasayet taṁ bhajet॥
"Shri Krishna is the Supreme Brahm. Even death fears Him. By knowing Him, jiva acquires the perfect knowledge of everything."
They further asked:
ब्रह्मवादिनो वदन्ति कस्मात् राधिकामुपासते ।
brahmavādino vadanti kasmāt rādhikāmupāsate ।
"Then why should we worship Shri Radha? Who is Shri Radha?"
The Vedas reply -
कृष्णेन आराध्यते इति राधा ।
kr̥ṣṇena ārādhyate iti rādhā ।
"The One, Who is worshipped even by the Supreme God Shri Krishna, is Shri Radha."
यस्यारेणुं पादयो विश्वभर्ता धरते मूर्ध्नि ।
यस्या अगम्यताम् श्रुतयो वदन्ति ।
सांशा कमला शैलपुत्री तां राधिकां शक्तिधात्रीं नमामः ।
अथर्व. राधिकोपनिषद्.
yasyāreṇuṁ pādayo viśvabhartā dharate mūrdhni ।
yasyā agamyatām śrutayo vadanti ।
sāṁśā kamalā śailaputrī tāṁ rādhikāṁ śaktidhātrīṁ namāmaḥ ।
atharva. rādhikopaniṣad.
"Shri Radha is that Superior most personality for whom Vedas proclaim that they cannot comprehend Her. The Supreme Lord Shri Krishna adores Her foot dust. The sovereign divine Goddesses Uma, Rama and Brahmani are the embodiment of just one power of Shri Radha. We offer millions of obeisance to that Supreme power known as Shri Radha."

In the next article we will elaborate on the divine introduction of Shri Radha.